diff --git a/composer.json b/composer.json
index fd3153f..0a3fb27 100644
--- a/composer.json
+++ b/composer.json
@@ -1,8 +1,8 @@
 {
-    "name": "skoro/php-gui",
-    "description": "Create desktop applications using native gui",
+    "name": "skoro/tkui",
+    "description": "Create desktop applications using Tk gui toolkit",
     "keywords": [
-        "gui", "ui", "desktop", "toolkit"
+        "gui", "ui", "desktop", "toolkit", "tcltk", "tk", "widget"
     ],
     "type": "library",
     "authors": [
@@ -21,7 +21,7 @@
     },
     "autoload": {
         "psr-4": {
-            "PhpGui\\": "src/"
+            "Tkui\\": "src/"
         }
     },
     "require-dev": {
@@ -30,7 +30,7 @@
     },
     "autoload-dev": {
         "psr-4": {
-            "PhpGui\\Tests\\": "tests/"
+            "Tkui\\Tests\\": "tests/"
         }
     },
     "scripts": {
diff --git a/demos/DemoAppWindow.php b/demos/DemoAppWindow.php
index 40b0535..0a1fce8 100644
--- a/demos/DemoAppWindow.php
+++ b/demos/DemoAppWindow.php
@@ -1,10 +1,10 @@
 <?php declare(strict_types=1);
 
-use PhpGui\Application;
-use PhpGui\DotEnv;
-use PhpGui\Image;
-use PhpGui\TclTk\TkAppFactory;
-use PhpGui\Windows\MainWindow;
+use Tkui\Application;
+use Tkui\DotEnv;
+use Tkui\Image;
+use Tkui\TclTk\TkAppFactory;
+use Tkui\Windows\MainWindow;
 
 require_once dirname(__DIR__) . '/vendor/autoload.php';
 
diff --git a/demos/buttons.php b/demos/buttons.php
index d5e5c16..a127401 100644
--- a/demos/buttons.php
+++ b/demos/buttons.php
@@ -1,16 +1,16 @@
 <?php
 
-use PhpGui\Layouts\Pack;
-use PhpGui\Widgets\Buttons\Button;
-use PhpGui\Widgets\Buttons\CheckButton;
-use PhpGui\Widgets\Buttons\MenuButton;
-use PhpGui\Widgets\Buttons\RadioButton;
-use PhpGui\Widgets\Label;
-use PhpGui\Widgets\LabelFrame;
-use PhpGui\Widgets\Menu\Menu;
-use PhpGui\Widgets\Menu\MenuItem;
-use PhpGui\Widgets\Menu\MenuItemGroup;
-use PhpGui\Widgets\RadioGroup;
+use Tkui\Layouts\Pack;
+use Tkui\Widgets\Buttons\Button;
+use Tkui\Widgets\Buttons\CheckButton;
+use Tkui\Widgets\Buttons\MenuButton;
+use Tkui\Widgets\Buttons\RadioButton;
+use Tkui\Widgets\Label;
+use Tkui\Widgets\LabelFrame;
+use Tkui\Widgets\Menu\Menu;
+use Tkui\Widgets\Menu\MenuItem;
+use Tkui\Widgets\Menu\MenuItemGroup;
+use Tkui\Widgets\RadioGroup;
 
 require_once dirname(__FILE__) . '/DemoAppWindow.php';
 
diff --git a/demos/combobox.php b/demos/combobox.php
index 78ef5a2..2795089 100644
--- a/demos/combobox.php
+++ b/demos/combobox.php
@@ -1,16 +1,16 @@
 <?php
 
-use PhpGui\Color;
-use PhpGui\Layouts\Pack;
-use PhpGui\Widgets\Buttons\Button;
-use PhpGui\Widgets\Buttons\CheckButton;
-use PhpGui\Widgets\Combobox;
-use PhpGui\Widgets\Entry;
-use PhpGui\Widgets\Frame;
-use PhpGui\Widgets\Label;
-use PhpGui\Widgets\LabelFrame;
-use PhpGui\Widgets\RadioGroup;
-use PhpGui\Widgets\Scrollbar;
+use Tkui\Color;
+use Tkui\Layouts\Pack;
+use Tkui\Widgets\Buttons\Button;
+use Tkui\Widgets\Buttons\CheckButton;
+use Tkui\Widgets\Combobox;
+use Tkui\Widgets\Entry;
+use Tkui\Widgets\Frame;
+use Tkui\Widgets\Label;
+use Tkui\Widgets\LabelFrame;
+use Tkui\Widgets\RadioGroup;
+use Tkui\Widgets\Scrollbar;
 
 require_once dirname(__FILE__) . '/DemoAppWindow.php';
 
diff --git a/demos/dialogs.php b/demos/dialogs.php
index fcf3cd6..2ebeb36 100644
--- a/demos/dialogs.php
+++ b/demos/dialogs.php
@@ -1,15 +1,15 @@
 <?php
 
-use PhpGui\Dialogs\ColorDialog;
-use PhpGui\Dialogs\DirectoryDialog;
-use PhpGui\Dialogs\FontDialog;
-use PhpGui\Dialogs\OpenFileDialog;
-use PhpGui\Dialogs\SaveFileDialog;
-use PhpGui\Font;
-use PhpGui\Layouts\Pack;
-use PhpGui\Widgets\Buttons\Button;
-use PhpGui\Widgets\Label;
-use PhpGui\Widgets\LabelFrame;
+use Tkui\Dialogs\ColorDialog;
+use Tkui\Dialogs\DirectoryDialog;
+use Tkui\Dialogs\FontDialog;
+use Tkui\Dialogs\OpenFileDialog;
+use Tkui\Dialogs\SaveFileDialog;
+use Tkui\Font;
+use Tkui\Layouts\Pack;
+use Tkui\Widgets\Buttons\Button;
+use Tkui\Widgets\Label;
+use Tkui\Widgets\LabelFrame;
 
 require_once dirname(__FILE__) . '/DemoAppWindow.php';
 
diff --git a/demos/listbox.php b/demos/listbox.php
index bc5f06d..f5a5ce4 100644
--- a/demos/listbox.php
+++ b/demos/listbox.php
@@ -1,14 +1,14 @@
 <?php
 
-use PhpGui\Layouts\Pack;
-use PhpGui\Widgets\Buttons\Button;
-use PhpGui\Widgets\Entry;
-use PhpGui\Widgets\Frame;
-use PhpGui\Widgets\Label;
-use PhpGui\Widgets\LabelFrame;
-use PhpGui\Widgets\Listbox;
-use PhpGui\Widgets\ListboxItem;
-use PhpGui\Widgets\Scrollbar;
+use Tkui\Layouts\Pack;
+use Tkui\Widgets\Buttons\Button;
+use Tkui\Widgets\Entry;
+use Tkui\Widgets\Frame;
+use Tkui\Widgets\Label;
+use Tkui\Widgets\LabelFrame;
+use Tkui\Widgets\Listbox;
+use Tkui\Widgets\ListboxItem;
+use Tkui\Widgets\Scrollbar;
 
 require_once dirname(__FILE__) . '/DemoAppWindow.php';
 
diff --git a/demos/menu.php b/demos/menu.php
index 04c974c..f744085 100644
--- a/demos/menu.php
+++ b/demos/menu.php
@@ -1,13 +1,13 @@
 <?php
 
-use PhpGui\Layouts\Pack;
-use PhpGui\Widgets\Menu\Menu;
-use PhpGui\Widgets\Menu\MenuCheckItem;
-use PhpGui\Widgets\Menu\MenuItem;
-use PhpGui\Widgets\Menu\MenuRadioGroup;
-use PhpGui\Widgets\Menu\MenuRadioItem;
-use PhpGui\Widgets\Scrollbar;
-use PhpGui\Widgets\Text\Text;
+use Tkui\Layouts\Pack;
+use Tkui\Widgets\Menu\Menu;
+use Tkui\Widgets\Menu\MenuCheckItem;
+use Tkui\Widgets\Menu\MenuItem;
+use Tkui\Widgets\Menu\MenuRadioGroup;
+use Tkui\Widgets\Menu\MenuRadioItem;
+use Tkui\Widgets\Scrollbar;
+use Tkui\Widgets\Text\Text;
 
 require_once dirname(__FILE__) . '/DemoAppWindow.php';
 
diff --git a/demos/messagebox.php b/demos/messagebox.php
index 19f2211..eeceeef 100644
--- a/demos/messagebox.php
+++ b/demos/messagebox.php
@@ -1,12 +1,12 @@
 <?php
 
-use PhpGui\Dialogs\MessageBox;
-use PhpGui\Layouts\Pack;
-use PhpGui\Widgets\Buttons\Button;
-use PhpGui\Widgets\Buttons\RadioButton;
-use PhpGui\Widgets\Frame;
-use PhpGui\Widgets\Label;
-use PhpGui\Widgets\RadioGroup;
+use Tkui\Dialogs\MessageBox;
+use Tkui\Layouts\Pack;
+use Tkui\Widgets\Buttons\Button;
+use Tkui\Widgets\Buttons\RadioButton;
+use Tkui\Widgets\Frame;
+use Tkui\Widgets\Label;
+use Tkui\Widgets\RadioGroup;
 
 require_once dirname(__FILE__) . '/DemoAppWindow.php';
 
diff --git a/demos/notebook.php b/demos/notebook.php
index 70c267d..a70230a 100644
--- a/demos/notebook.php
+++ b/demos/notebook.php
@@ -1,12 +1,12 @@
 <?php declare(strict_types=1);
 
-use PhpGui\Layouts\Pack;
-use PhpGui\Widgets\Buttons\Button;
-use PhpGui\Widgets\Frame;
-use PhpGui\Widgets\Label;
-use PhpGui\Widgets\LabelFrame;
-use PhpGui\Widgets\Notebook;
-use PhpGui\Widgets\NotebookTab;
+use Tkui\Layouts\Pack;
+use Tkui\Widgets\Buttons\Button;
+use Tkui\Widgets\Frame;
+use Tkui\Widgets\Label;
+use Tkui\Widgets\LabelFrame;
+use Tkui\Widgets\Notebook;
+use Tkui\Widgets\NotebookTab;
 
 require_once dirname(__FILE__) . '/DemoAppWindow.php';
 
diff --git a/demos/panedwindow.php b/demos/panedwindow.php
index 5969c00..7d81dda 100644
--- a/demos/panedwindow.php
+++ b/demos/panedwindow.php
@@ -1,9 +1,9 @@
 <?php
 
-use PhpGui\Layouts\Pack;
-use PhpGui\Widgets\Label;
-use PhpGui\Widgets\LabelFrame;
-use PhpGui\Widgets\PanedWindow;
+use Tkui\Layouts\Pack;
+use Tkui\Widgets\Label;
+use Tkui\Widgets\LabelFrame;
+use Tkui\Widgets\PanedWindow;
 
 require_once dirname(__FILE__) . '/DemoAppWindow.php';
 
diff --git a/demos/place_layout.php b/demos/place_layout.php
index 76f152b..a977eb6 100644
--- a/demos/place_layout.php
+++ b/demos/place_layout.php
@@ -1,7 +1,7 @@
 <?php
 
-use PhpGui\Widgets\Buttons\Button;
-use PhpGui\Widgets\Label;
+use Tkui\Widgets\Buttons\Button;
+use Tkui\Widgets\Label;
 
 require_once dirname(__FILE__) . '/DemoAppWindow.php';
 
diff --git a/demos/sizegrip.php b/demos/sizegrip.php
index 9665843..3b761a9 100644
--- a/demos/sizegrip.php
+++ b/demos/sizegrip.php
@@ -1,10 +1,10 @@
 <?php declare(strict_types=1);
 
-use PhpGui\Layouts\Pack;
-use PhpGui\Widgets\Frame;
-use PhpGui\Widgets\Label;
-use PhpGui\Widgets\Separator;
-use PhpGui\Widgets\Sizegrip;
+use Tkui\Layouts\Pack;
+use Tkui\Widgets\Frame;
+use Tkui\Widgets\Label;
+use Tkui\Widgets\Separator;
+use Tkui\Widgets\Sizegrip;
 
 require_once dirname(__FILE__) . '/DemoAppWindow.php';
 
diff --git a/demos/spinbox.php b/demos/spinbox.php
index 8793f1e..e84de68 100644
--- a/demos/spinbox.php
+++ b/demos/spinbox.php
@@ -1,7 +1,7 @@
 <?php
 
-use PhpGui\Layouts\Pack;
-use PhpGui\Widgets\Spinbox;
+use Tkui\Layouts\Pack;
+use Tkui\Widgets\Spinbox;
 
 require_once dirname(__FILE__) . '/DemoAppWindow.php';
 
diff --git a/demos/text.php b/demos/text.php
index 2768685..f90b9dc 100644
--- a/demos/text.php
+++ b/demos/text.php
@@ -1,17 +1,17 @@
 <?php
 
-use PhpGui\Color;
-use PhpGui\Image;
-use PhpGui\Layouts\Pack;
-use PhpGui\TclTk\TkFont;
-use PhpGui\Widgets\Buttons\Button;
-use PhpGui\Widgets\Entry;
-use PhpGui\Widgets\Frame;
-use PhpGui\Widgets\Scrollbar;
-use PhpGui\Widgets\Text\SearchOptions;
-use PhpGui\Widgets\Text\Text;
-use PhpGui\Widgets\Text\TextIndex;
-use PhpGui\Widgets\Text\TextStyle;
+use Tkui\Color;
+use Tkui\Image;
+use Tkui\Layouts\Pack;
+use Tkui\TclTk\TkFont;
+use Tkui\Widgets\Buttons\Button;
+use Tkui\Widgets\Entry;
+use Tkui\Widgets\Frame;
+use Tkui\Widgets\Scrollbar;
+use Tkui\Widgets\Text\SearchOptions;
+use Tkui\Widgets\Text\Text;
+use Tkui\Widgets\Text\TextIndex;
+use Tkui\Widgets\Text\TextStyle;
 
 require_once dirname(__FILE__) . '/DemoAppWindow.php';
 
diff --git a/demos/window.php b/demos/window.php
index eb017e6..f54fef4 100644
--- a/demos/window.php
+++ b/demos/window.php
@@ -1,8 +1,8 @@
 <?php
 
-use PhpGui\Widgets\Buttons\Button;
-use PhpGui\Windows\ChildWindow;
-use PhpGui\Windows\Window;
+use Tkui\Widgets\Buttons\Button;
+use Tkui\Windows\ChildWindow;
+use Tkui\Windows\Window;
 
 require_once dirname(__FILE__) . '/DemoAppWindow.php';
 
diff --git a/src/AppFactory.php b/src/AppFactory.php
index 24f4d8d..47d9ad9 100644
--- a/src/AppFactory.php
+++ b/src/AppFactory.php
@@ -1,6 +1,6 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui;
+namespace Tkui;
 
 /**
  * The application factory.
diff --git a/src/Application.php b/src/Application.php
index 74108a2..5e8b643 100644
--- a/src/Application.php
+++ b/src/Application.php
@@ -1,6 +1,6 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui;
+namespace Tkui;
 
 /**
  * The application instance.
diff --git a/src/Bindings.php b/src/Bindings.php
index 608ba88..fa96387 100644
--- a/src/Bindings.php
+++ b/src/Bindings.php
@@ -1,8 +1,8 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui;
+namespace Tkui;
 
-use PhpGui\Widgets\Widget;
+use Tkui\Widgets\Widget;
 
 /**
  * Let you attach/detach widget bindings.
diff --git a/src/Color.php b/src/Color.php
index 132f267..8d2f253 100644
--- a/src/Color.php
+++ b/src/Color.php
@@ -1,6 +1,6 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui;
+namespace Tkui;
 
 use InvalidArgumentException;
 
diff --git a/src/ColorNames.php b/src/ColorNames.php
index 5415beb..887e167 100644
--- a/src/ColorNames.php
+++ b/src/ColorNames.php
@@ -1,6 +1,6 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui;
+namespace Tkui;
 
 /**
  * DON'T EDIT THIS CLASS !
diff --git a/src/Dialogs/ColorDialog.php b/src/Dialogs/ColorDialog.php
index 06c9aaf..da6d97c 100644
--- a/src/Dialogs/ColorDialog.php
+++ b/src/Dialogs/ColorDialog.php
@@ -1,8 +1,8 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Dialogs;
+namespace Tkui\Dialogs;
 
-use PhpGui\Options;
+use Tkui\Options;
 
 /**
  * @link https://www.tcl.tk/man/tcl8.6/TkCmd/chooseColor.htm
diff --git a/src/Dialogs/Dialog.php b/src/Dialogs/Dialog.php
index 50225ca..67634c6 100644
--- a/src/Dialogs/Dialog.php
+++ b/src/Dialogs/Dialog.php
@@ -1,11 +1,11 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Dialogs;
+namespace Tkui\Dialogs;
 
-use PhpGui\TclTk\Exceptions\TkException;
-use PhpGui\Options;
-use PhpGui\Windows\ModalWindow;
-use PhpGui\Windows\Window;
+use Tkui\TclTk\Exceptions\TkException;
+use Tkui\Options;
+use Tkui\Windows\ModalWindow;
+use Tkui\Windows\Window;
 
 /**
  * Base class for dialog windows
diff --git a/src/Dialogs/DirectoryDialog.php b/src/Dialogs/DirectoryDialog.php
index b4469ea..ebfc986 100644
--- a/src/Dialogs/DirectoryDialog.php
+++ b/src/Dialogs/DirectoryDialog.php
@@ -1,8 +1,8 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Dialogs;
+namespace Tkui\Dialogs;
 
-use PhpGui\Options;
+use Tkui\Options;
 
 /**
  * @link https://www.tcl.tk/man/tcl8.6/TkCmd/chooseDirectory.htm
diff --git a/src/Dialogs/FileDialog.php b/src/Dialogs/FileDialog.php
index d2d93fc..5e3ce24 100644
--- a/src/Dialogs/FileDialog.php
+++ b/src/Dialogs/FileDialog.php
@@ -1,9 +1,9 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Dialogs;
+namespace Tkui\Dialogs;
 
-use PhpGui\Options;
-use PhpGui\Widgets\Window;
+use Tkui\Options;
+use Tkui\Widgets\Window;
 
 /**
  * @property string $defaultExtension
diff --git a/src/Dialogs/FileType.php b/src/Dialogs/FileType.php
index 2ca4681..0c761bf 100644
--- a/src/Dialogs/FileType.php
+++ b/src/Dialogs/FileType.php
@@ -1,8 +1,8 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Dialogs;
+namespace Tkui\Dialogs;
 
-use PhpGui\TclTk\Tcl;
+use Tkui\TclTk\Tcl;
 
 // TODO: implement Stringable
 /**
diff --git a/src/Dialogs/FontDialog.php b/src/Dialogs/FontDialog.php
index 63e3350..0f4a3d7 100644
--- a/src/Dialogs/FontDialog.php
+++ b/src/Dialogs/FontDialog.php
@@ -1,12 +1,12 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Dialogs;
+namespace Tkui\Dialogs;
 
-use PhpGui\FontManager;
-use PhpGui\Options;
-use PhpGui\Widgets\Container;
-use PhpGui\Widgets\Widget;
-use PhpGui\Windows\Window;
+use Tkui\FontManager;
+use Tkui\Options;
+use Tkui\Widgets\Container;
+use Tkui\Widgets\Widget;
+use Tkui\Windows\Window;
 
 /**
  * @link https://www.tcl.tk/man/tcl8.6/TkCmd/fontchooser.htm
diff --git a/src/Dialogs/MessageBox.php b/src/Dialogs/MessageBox.php
index d044330..c07af30 100644
--- a/src/Dialogs/MessageBox.php
+++ b/src/Dialogs/MessageBox.php
@@ -1,9 +1,9 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Dialogs;
+namespace Tkui\Dialogs;
 
-use PhpGui\Options;
-use PhpGui\Windows\Window;
+use Tkui\Options;
+use Tkui\Windows\Window;
 
 /**
  * MessageBox pops up a message and wait for user response.
diff --git a/src/Dialogs/OpenFileDialog.php b/src/Dialogs/OpenFileDialog.php
index 3cc2a7d..d65cc72 100644
--- a/src/Dialogs/OpenFileDialog.php
+++ b/src/Dialogs/OpenFileDialog.php
@@ -1,6 +1,6 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Dialogs;
+namespace Tkui\Dialogs;
 
 /**
  * @link https://www.tcl.tk/man/tcl8.6/TkCmd/getOpenFile.htm
diff --git a/src/Dialogs/SaveFileDialog.php b/src/Dialogs/SaveFileDialog.php
index 9baec91..cd064ff 100644
--- a/src/Dialogs/SaveFileDialog.php
+++ b/src/Dialogs/SaveFileDialog.php
@@ -1,8 +1,8 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Dialogs;
+namespace Tkui\Dialogs;
 
-use PhpGui\Options;
+use Tkui\Options;
 
 /**
  * @link https://www.tcl.tk/man/tcl8.6/TkCmd/getOpenFile.htm
diff --git a/src/DotEnv.php b/src/DotEnv.php
index dca6412..503dc1c 100644
--- a/src/DotEnv.php
+++ b/src/DotEnv.php
@@ -1,6 +1,6 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui;
+namespace Tkui;
 
 use RuntimeException;
 use M1\Env\Parser as EnvParser;
diff --git a/src/Environment.php b/src/Environment.php
index f1371b3..a31aeef 100644
--- a/src/Environment.php
+++ b/src/Environment.php
@@ -1,6 +1,6 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui;
+namespace Tkui;
 
 interface Environment
 {
diff --git a/src/Evaluator.php b/src/Evaluator.php
index 82fe823..98eb45f 100644
--- a/src/Evaluator.php
+++ b/src/Evaluator.php
@@ -1,9 +1,9 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui;
+namespace Tkui;
 
-use PhpGui\TclTk\Variable;
-use PhpGui\Widgets\Widget;
+use Tkui\TclTk\Variable;
+use Tkui\Widgets\Widget;
 
 /**
  * Provides the access to low-level API.
diff --git a/src/Exceptions/Exception.php b/src/Exceptions/Exception.php
index 1176bce..2219d47 100644
--- a/src/Exceptions/Exception.php
+++ b/src/Exceptions/Exception.php
@@ -1,6 +1,6 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Exceptions;
+namespace Tkui\Exceptions;
 
 /**
  * The root exception.
diff --git a/src/Exceptions/UninitializedVariableException.php b/src/Exceptions/UninitializedVariableException.php
index 71dcb95..d75c2a0 100644
--- a/src/Exceptions/UninitializedVariableException.php
+++ b/src/Exceptions/UninitializedVariableException.php
@@ -1,6 +1,6 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Exceptions;
+namespace Tkui\Exceptions;
 
 use RuntimeException;
 
diff --git a/src/Exceptions/UnsupportedOSException.php b/src/Exceptions/UnsupportedOSException.php
index 4cf9bb2..e9b1b44 100644
--- a/src/Exceptions/UnsupportedOSException.php
+++ b/src/Exceptions/UnsupportedOSException.php
@@ -1,8 +1,8 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Exceptions;
+namespace Tkui\Exceptions;
 
-use PhpGui\System\OS;
+use Tkui\System\OS;
 
 class UnsupportedOSException extends Exception
 {
diff --git a/src/Font.php b/src/Font.php
index 0153651..513c97b 100644
--- a/src/Font.php
+++ b/src/Font.php
@@ -1,6 +1,6 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui;
+namespace Tkui;
 
 use InvalidArgumentException;
 use SplObserver;
diff --git a/src/FontManager.php b/src/FontManager.php
index d8ef5b0..97f27be 100644
--- a/src/FontManager.php
+++ b/src/FontManager.php
@@ -1,6 +1,6 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui;
+namespace Tkui;
 
 /**
  * Font manager.
diff --git a/src/HasLogger.php b/src/HasLogger.php
index 18506b3..912d008 100644
--- a/src/HasLogger.php
+++ b/src/HasLogger.php
@@ -1,6 +1,6 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui;
+namespace Tkui;
 
 use Psr\Log\LoggerInterface;
 
diff --git a/src/Image.php b/src/Image.php
index 0bfe67b..d500eb6 100644
--- a/src/Image.php
+++ b/src/Image.php
@@ -1,6 +1,6 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui;
+namespace Tkui;
 
 use Stringable;
 
diff --git a/src/ImageFactory.php b/src/ImageFactory.php
index 8e506d4..66eeb2d 100644
--- a/src/ImageFactory.php
+++ b/src/ImageFactory.php
@@ -1,6 +1,6 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui;
+namespace Tkui;
 
 interface ImageFactory
 {
diff --git a/src/Layouts/BaseManager.php b/src/Layouts/BaseManager.php
index d7da940..dda8102 100644
--- a/src/Layouts/BaseManager.php
+++ b/src/Layouts/BaseManager.php
@@ -1,10 +1,10 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Layouts;
+namespace Tkui\Layouts;
 
-use PhpGui\Evaluator;
-use PhpGui\Options;
-use PhpGui\Widgets\Widget;
+use Tkui\Evaluator;
+use Tkui\Options;
+use Tkui\Widgets\Widget;
 
 /**
  * Base layout manager.
diff --git a/src/Layouts/Grid.php b/src/Layouts/Grid.php
index fea4c7f..9bd7be2 100644
--- a/src/Layouts/Grid.php
+++ b/src/Layouts/Grid.php
@@ -1,9 +1,9 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Layouts;
+namespace Tkui\Layouts;
 
-use PhpGui\Options;
-use PhpGui\Widgets\Widget;
+use Tkui\Options;
+use Tkui\Widgets\Widget;
 
 /**
  * grid geometry manager.
diff --git a/src/Layouts/LayoutManager.php b/src/Layouts/LayoutManager.php
index c06fefa..c65b9b4 100644
--- a/src/Layouts/LayoutManager.php
+++ b/src/Layouts/LayoutManager.php
@@ -1,8 +1,8 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Layouts;
+namespace Tkui\Layouts;
 
-use PhpGui\Widgets\Widget;
+use Tkui\Widgets\Widget;
 
 /**
  * Layout manager interface.
diff --git a/src/Layouts/Pack.php b/src/Layouts/Pack.php
index 6feaff0..73e3be7 100644
--- a/src/Layouts/Pack.php
+++ b/src/Layouts/Pack.php
@@ -1,8 +1,8 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Layouts;
+namespace Tkui\Layouts;
 
-use PhpGui\Options;
+use Tkui\Options;
 
 /**
  * pack geometry manager.
diff --git a/src/Layouts/Place.php b/src/Layouts/Place.php
index fb5470d..52ef613 100644
--- a/src/Layouts/Place.php
+++ b/src/Layouts/Place.php
@@ -1,8 +1,8 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Layouts;
+namespace Tkui\Layouts;
 
-use PhpGui\Options;
+use Tkui\Options;
 
 /**
  * Geometry manager allows fixed placement.
diff --git a/src/Options.php b/src/Options.php
index 47075e5..4a088da 100644
--- a/src/Options.php
+++ b/src/Options.php
@@ -1,10 +1,10 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui;
+namespace Tkui;
 
 use InvalidArgumentException;
-use PhpGui\Widgets\Widget;
-use PhpGui\TclTk\Tcl;
+use Tkui\Widgets\Widget;
+use Tkui\TclTk\Tcl;
 
 /**
  * Tcl command options.
diff --git a/src/System/FFILoader.php b/src/System/FFILoader.php
index 2cd60c1..0a81855 100644
--- a/src/System/FFILoader.php
+++ b/src/System/FFILoader.php
@@ -1,6 +1,6 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\System;
+namespace Tkui\System;
 
 use FFI;
 use RuntimeException;
diff --git a/src/System/OS.php b/src/System/OS.php
index 3003b3e..4b52da9 100644
--- a/src/System/OS.php
+++ b/src/System/OS.php
@@ -1,6 +1,6 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\System;
+namespace Tkui\System;
 
 class OS
 {
diff --git a/src/TclTk/Exceptions/EvalException.php b/src/TclTk/Exceptions/EvalException.php
index d77e73f..a13620d 100644
--- a/src/TclTk/Exceptions/EvalException.php
+++ b/src/TclTk/Exceptions/EvalException.php
@@ -1,8 +1,8 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\TclTk\Exceptions;
+namespace Tkui\TclTk\Exceptions;
 
-use PhpGui\TclTk\Interp;
+use Tkui\TclTk\Interp;
 
 class EvalException extends TclInterpException
 {
diff --git a/src/TclTk/Exceptions/TclException.php b/src/TclTk/Exceptions/TclException.php
index 5019755..80fb30f 100644
--- a/src/TclTk/Exceptions/TclException.php
+++ b/src/TclTk/Exceptions/TclException.php
@@ -1,8 +1,8 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\TclTk\Exceptions;
+namespace Tkui\TclTk\Exceptions;
 
-use PhpGui\Exceptions\Exception;
+use Tkui\Exceptions\Exception;
 
 class TclException extends Exception
 {
diff --git a/src/TclTk/Exceptions/TclInterpException.php b/src/TclTk/Exceptions/TclInterpException.php
index 1942e9d..1433666 100644
--- a/src/TclTk/Exceptions/TclInterpException.php
+++ b/src/TclTk/Exceptions/TclInterpException.php
@@ -1,8 +1,8 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\TclTk\Exceptions;
+namespace Tkui\TclTk\Exceptions;
 
-use PhpGui\TclTk\Interp;
+use Tkui\TclTk\Interp;
 
 class TclInterpException extends TclException
 {
diff --git a/src/TclTk/Exceptions/TkException.php b/src/TclTk/Exceptions/TkException.php
index 3f60869..c2b09e5 100644
--- a/src/TclTk/Exceptions/TkException.php
+++ b/src/TclTk/Exceptions/TkException.php
@@ -1,6 +1,6 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\TclTk\Exceptions;
+namespace Tkui\TclTk\Exceptions;
 
 class TkException extends TclException
 {
diff --git a/src/TclTk/Interp.php b/src/TclTk/Interp.php
index f2ff8ce..2a628a5 100644
--- a/src/TclTk/Interp.php
+++ b/src/TclTk/Interp.php
@@ -1,11 +1,11 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\TclTk;
+namespace Tkui\TclTk;
 
 use FFI\CData;
-use PhpGui\HasLogger;
-use PhpGui\TclTk\Exceptions\TclException;
-use PhpGui\TclTk\Exceptions\TclInterpException;
+use Tkui\HasLogger;
+use Tkui\TclTk\Exceptions\TclException;
+use Tkui\TclTk\Exceptions\TclInterpException;
 
 /**
  * Tcl interpreter implementation.
diff --git a/src/TclTk/Tcl.php b/src/TclTk/Tcl.php
index 152d6c5..cc2926b 100644
--- a/src/TclTk/Tcl.php
+++ b/src/TclTk/Tcl.php
@@ -1,12 +1,12 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\TclTk;
+namespace Tkui\TclTk;
 
 use FFI;
 use FFI\CData;
-use PhpGui\TclTk\Exceptions\EvalException;
-use PhpGui\TclTk\Exceptions\TclException;
-use PhpGui\TclTk\Exceptions\TclInterpException;
+use Tkui\TclTk\Exceptions\EvalException;
+use Tkui\TclTk\Exceptions\TclException;
+use Tkui\TclTk\Exceptions\TclInterpException;
 
 /**
  * Low-level interface to Tcl FFI.
diff --git a/src/TclTk/Tk.php b/src/TclTk/Tk.php
index f7d79f2..6af33b9 100644
--- a/src/TclTk/Tk.php
+++ b/src/TclTk/Tk.php
@@ -1,10 +1,10 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\TclTk;
+namespace Tkui\TclTk;
 
 use FFI;
 use FFI\CData;
-use PhpGui\TclTk\Exceptions\TclException;
+use Tkui\TclTk\Exceptions\TclException;
 
 /**
  * Low-level interface to Tk FFI.
diff --git a/src/TclTk/TkAppFactory.php b/src/TclTk/TkAppFactory.php
index 1f987b7..f607afe 100644
--- a/src/TclTk/TkAppFactory.php
+++ b/src/TclTk/TkAppFactory.php
@@ -1,15 +1,15 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\TclTk;
+namespace Tkui\TclTk;
 
 use Monolog\Formatter\LineFormatter;
 use Monolog\Handler\StreamHandler;
 use Monolog\Logger;
-use PhpGui\AppFactory;
-use PhpGui\Environment;
-use PhpGui\Exceptions\UnsupportedOSException;
-use PhpGui\System\FFILoader;
-use PhpGui\System\OS;
+use Tkui\AppFactory;
+use Tkui\Environment;
+use Tkui\Exceptions\UnsupportedOSException;
+use Tkui\System\FFILoader;
+use Tkui\System\OS;
 
 /**
  * Tk implementation of Application Factory.
diff --git a/src/TclTk/TkApplication.php b/src/TclTk/TkApplication.php
index 52d4744..068d8d4 100644
--- a/src/TclTk/TkApplication.php
+++ b/src/TclTk/TkApplication.php
@@ -1,15 +1,15 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\TclTk;
-
-use PhpGui\Application;
-use PhpGui\Bindings;
-use PhpGui\FontManager;
-use PhpGui\HasLogger;
-use PhpGui\ImageFactory;
-use PhpGui\TclTk\Exceptions\TclException;
-use PhpGui\TclTk\Exceptions\TclInterpException;
-use PhpGui\Widgets\Widget;
+namespace Tkui\TclTk;
+
+use Tkui\Application;
+use Tkui\Bindings;
+use Tkui\FontManager;
+use Tkui\HasLogger;
+use Tkui\ImageFactory;
+use Tkui\TclTk\Exceptions\TclException;
+use Tkui\TclTk\Exceptions\TclInterpException;
+use Tkui\Widgets\Widget;
 
 /**
  * Main application.
diff --git a/src/TclTk/TkBindings.php b/src/TclTk/TkBindings.php
index 20645c8..976a35d 100644
--- a/src/TclTk/TkBindings.php
+++ b/src/TclTk/TkBindings.php
@@ -1,9 +1,9 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\TclTk;
+namespace Tkui\TclTk;
 
-use PhpGui\Bindings;
-use PhpGui\Widgets\Widget;
+use Tkui\Bindings;
+use Tkui\Widgets\Widget;
 
 class TkBindings implements Bindings
 {
diff --git a/src/TclTk/TkFont.php b/src/TclTk/TkFont.php
index e8d3d5a..fa99194 100644
--- a/src/TclTk/TkFont.php
+++ b/src/TclTk/TkFont.php
@@ -1,8 +1,8 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\TclTk;
+namespace Tkui\TclTk;
 
-use PhpGui\Font;
+use Tkui\Font;
 
 final class TkFont extends Font
 {
diff --git a/src/TclTk/TkFontManager.php b/src/TclTk/TkFontManager.php
index fae41a3..d4478e4 100644
--- a/src/TclTk/TkFontManager.php
+++ b/src/TclTk/TkFontManager.php
@@ -1,9 +1,9 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\TclTk;
+namespace Tkui\TclTk;
 
-use PhpGui\Font;
-use PhpGui\FontManager;
+use Tkui\Font;
+use Tkui\FontManager;
 
 /**
  * Tk Font Manager.
diff --git a/src/TclTk/TkFontOptions.php b/src/TclTk/TkFontOptions.php
index 31138be..d573ede 100644
--- a/src/TclTk/TkFontOptions.php
+++ b/src/TclTk/TkFontOptions.php
@@ -1,8 +1,8 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\TclTk;
+namespace Tkui\TclTk;
 
-use PhpGui\Options;
+use Tkui\Options;
 
 /**
  * @property string $family
diff --git a/src/TclTk/TkImage.php b/src/TclTk/TkImage.php
index 8879c5d..bfbc5d6 100644
--- a/src/TclTk/TkImage.php
+++ b/src/TclTk/TkImage.php
@@ -1,8 +1,8 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\TclTk;
+namespace Tkui\TclTk;
 
-use PhpGui\Image;
+use Tkui\Image;
 
 /**
  * Tk implementation of Image.
diff --git a/src/TclTk/TkImageFactory.php b/src/TclTk/TkImageFactory.php
index 81a0f7d..5f96c10 100644
--- a/src/TclTk/TkImageFactory.php
+++ b/src/TclTk/TkImageFactory.php
@@ -1,9 +1,9 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\TclTk;
+namespace Tkui\TclTk;
 
-use PhpGui\Image;
-use PhpGui\ImageFactory;
+use Tkui\Image;
+use Tkui\ImageFactory;
 
 /**
  * Tk implementation of Image Factory.
diff --git a/src/TclTk/TkThemeManager.php b/src/TclTk/TkThemeManager.php
index 50718a6..4db4213 100644
--- a/src/TclTk/TkThemeManager.php
+++ b/src/TclTk/TkThemeManager.php
@@ -1,8 +1,8 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\TclTk;
+namespace Tkui\TclTk;
 
-use PhpGui\ThemeManager;
+use Tkui\ThemeManager;
 
 /**
  * Implementation of Ttk style themes.
diff --git a/src/TclTk/TkWindowManager.php b/src/TclTk/TkWindowManager.php
index c057586..46bba38 100644
--- a/src/TclTk/TkWindowManager.php
+++ b/src/TclTk/TkWindowManager.php
@@ -1,10 +1,10 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\TclTk;
+namespace Tkui\TclTk;
 
-use PhpGui\Evaluator;
-use PhpGui\WindowManager;
-use PhpGui\Windows\Window;
+use Tkui\Evaluator;
+use Tkui\WindowManager;
+use Tkui\Windows\Window;
 
 /**
  * Tk implementation of Window Manager.
diff --git a/src/TclTk/Variable.php b/src/TclTk/Variable.php
index 9bdda8d..874c966 100644
--- a/src/TclTk/Variable.php
+++ b/src/TclTk/Variable.php
@@ -1,6 +1,6 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\TclTk;
+namespace Tkui\TclTk;
 
 use FFI\CData;
 
diff --git a/src/ThemeManager.php b/src/ThemeManager.php
index 1c4ea7f..5846118 100644
--- a/src/ThemeManager.php
+++ b/src/ThemeManager.php
@@ -1,6 +1,6 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui;
+namespace Tkui;
 
 /**
  * The application theme manager.
diff --git a/src/Widgets/Buttons/Button.php b/src/Widgets/Buttons/Button.php
index f91d5d4..2723f5a 100644
--- a/src/Widgets/Buttons/Button.php
+++ b/src/Widgets/Buttons/Button.php
@@ -1,9 +1,9 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets\Buttons;
+namespace Tkui\Widgets\Buttons;
 
-use PhpGui\Options;
-use PhpGui\Widgets\Container;
+use Tkui\Options;
+use Tkui\Widgets\Container;
 
 /**
  * @link https://www.tcl.tk/man/tcl8.6/TkCmd/ttk_button.htm
diff --git a/src/Widgets/Buttons/CheckButton.php b/src/Widgets/Buttons/CheckButton.php
index d482412..80e4f24 100644
--- a/src/Widgets/Buttons/CheckButton.php
+++ b/src/Widgets/Buttons/CheckButton.php
@@ -1,10 +1,10 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets\Buttons;
+namespace Tkui\Widgets\Buttons;
 
-use PhpGui\Options;
-use PhpGui\TclTk\Variable;
-use PhpGui\Widgets\Container;
+use Tkui\Options;
+use Tkui\TclTk\Variable;
+use Tkui\Widgets\Container;
 
 /**
  * @link https://www.tcl.tk/man/tcl8.6/TkCmd/ttk_checkbutton.htm
diff --git a/src/Widgets/Buttons/Command.php b/src/Widgets/Buttons/Command.php
index 0e7e606..260a65c 100644
--- a/src/Widgets/Buttons/Command.php
+++ b/src/Widgets/Buttons/Command.php
@@ -1,6 +1,6 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets\Buttons;
+namespace Tkui\Widgets\Buttons;
 
 use InvalidArgumentException;
 
diff --git a/src/Widgets/Buttons/GenericButton.php b/src/Widgets/Buttons/GenericButton.php
index aa3564a..d90f37b 100644
--- a/src/Widgets/Buttons/GenericButton.php
+++ b/src/Widgets/Buttons/GenericButton.php
@@ -1,12 +1,12 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets\Buttons;
+namespace Tkui\Widgets\Buttons;
 
-use PhpGui\Options;
-use PhpGui\Widgets\Common\Clickable;
-use PhpGui\Widgets\Common\DetectUnderline;
-use PhpGui\Widgets\Container;
-use PhpGui\Widgets\TtkWidget;
+use Tkui\Options;
+use Tkui\Widgets\Common\Clickable;
+use Tkui\Widgets\Common\DetectUnderline;
+use Tkui\Widgets\Container;
+use Tkui\Widgets\TtkWidget;
 
 /**
  * @property callable $command
diff --git a/src/Widgets/Buttons/MenuButton.php b/src/Widgets/Buttons/MenuButton.php
index 7dd4372..1ad5c85 100644
--- a/src/Widgets/Buttons/MenuButton.php
+++ b/src/Widgets/Buttons/MenuButton.php
@@ -1,10 +1,10 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets\Buttons;
+namespace Tkui\Widgets\Buttons;
 
-use PhpGui\Options;
-use PhpGui\Widgets\Container;
-use PhpGui\Widgets\Menu\Menu;
+use Tkui\Options;
+use Tkui\Widgets\Container;
+use Tkui\Widgets\Menu\Menu;
 
 /**
  * Implementation of menubutton.
diff --git a/src/Widgets/Buttons/RadioButton.php b/src/Widgets/Buttons/RadioButton.php
index 43eeea2..4a31f27 100644
--- a/src/Widgets/Buttons/RadioButton.php
+++ b/src/Widgets/Buttons/RadioButton.php
@@ -1,10 +1,10 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets\Buttons;
+namespace Tkui\Widgets\Buttons;
 
-use PhpGui\Options;
-use PhpGui\TclTk\Variable;
-use PhpGui\Widgets\Container;
+use Tkui\Options;
+use Tkui\TclTk\Variable;
+use Tkui\Widgets\Container;
 
 /**
  * @link https://www.tcl.tk/man/tcl8.6/TkCmd/ttk_radiobutton.htm
diff --git a/src/Widgets/Buttons/SelectableButton.php b/src/Widgets/Buttons/SelectableButton.php
index d251163..50d18f6 100644
--- a/src/Widgets/Buttons/SelectableButton.php
+++ b/src/Widgets/Buttons/SelectableButton.php
@@ -1,8 +1,8 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets\Buttons;
+namespace Tkui\Widgets\Buttons;
 
-use PhpGui\Widgets\Common\ValueInVariable;
+use Tkui\Widgets\Common\ValueInVariable;
 
 /**
  * Contract for buttons which can be selected or deselected.
diff --git a/src/Widgets/Buttons/SwitchableButton.php b/src/Widgets/Buttons/SwitchableButton.php
index 99629eb..463d036 100644
--- a/src/Widgets/Buttons/SwitchableButton.php
+++ b/src/Widgets/Buttons/SwitchableButton.php
@@ -1,10 +1,10 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets\Buttons;
+namespace Tkui\Widgets\Buttons;
 
-use PhpGui\Options;
-use PhpGui\TclTk\Variable;
-use PhpGui\Widgets\Container;
+use Tkui\Options;
+use Tkui\TclTk\Variable;
+use Tkui\Widgets\Container;
 
 /**
  * The base class for buttons that can be switched.
diff --git a/src/Widgets/Combobox.php b/src/Widgets/Combobox.php
index ae41f89..6cb02c7 100644
--- a/src/Widgets/Combobox.php
+++ b/src/Widgets/Combobox.php
@@ -1,12 +1,12 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets;
+namespace Tkui\Widgets;
 
-use PhpGui\Options;
-use PhpGui\TclTk\Tcl;
-use PhpGui\TclTk\Variable;
-use PhpGui\Widgets\Common\ValueInVariable;
-use PhpGui\Widgets\Consts\Justify;
+use Tkui\Options;
+use Tkui\TclTk\Tcl;
+use Tkui\TclTk\Variable;
+use Tkui\Widgets\Common\ValueInVariable;
+use Tkui\Widgets\Consts\Justify;
 
 /**
  * @link https://www.tcl.tk/man/tcl8.6/TkCmd/ttk_combobox.htm
diff --git a/src/Widgets/Common/Clickable.php b/src/Widgets/Common/Clickable.php
index b224134..f741c81 100644
--- a/src/Widgets/Common/Clickable.php
+++ b/src/Widgets/Common/Clickable.php
@@ -1,6 +1,6 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets\Common;
+namespace Tkui\Widgets\Common;
 
 /**
  * The widget that can handle 'click' event from the user.
diff --git a/src/Widgets/Common/DetectUnderline.php b/src/Widgets/Common/DetectUnderline.php
index c6d77e5..9974ba8 100644
--- a/src/Widgets/Common/DetectUnderline.php
+++ b/src/Widgets/Common/DetectUnderline.php
@@ -1,6 +1,6 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets\Common;
+namespace Tkui\Widgets\Common;
 
 /**
  * Helper for detecting index for the "underline" property.
diff --git a/src/Widgets/Common/Editable.php b/src/Widgets/Common/Editable.php
index 1427b06..a24597a 100644
--- a/src/Widgets/Common/Editable.php
+++ b/src/Widgets/Common/Editable.php
@@ -1,6 +1,6 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets\Common;
+namespace Tkui\Widgets\Common;
 
 /**
  * Widgets that can edit their content.
diff --git a/src/Widgets/Common/ValueInVariable.php b/src/Widgets/Common/ValueInVariable.php
index f1c5980..6e85f58 100644
--- a/src/Widgets/Common/ValueInVariable.php
+++ b/src/Widgets/Common/ValueInVariable.php
@@ -1,6 +1,6 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets\Common;
+namespace Tkui\Widgets\Common;
 
 /**
  * Widgets that contains their value in the variable.
diff --git a/src/Widgets/Consts/Anchor.php b/src/Widgets/Consts/Anchor.php
index 1aaf14d..b131aec 100644
--- a/src/Widgets/Consts/Anchor.php
+++ b/src/Widgets/Consts/Anchor.php
@@ -1,6 +1,6 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets\Consts;
+namespace Tkui\Widgets\Consts;
 
 /**
  * Values for 'anchor' property.
diff --git a/src/Widgets/Consts/Justify.php b/src/Widgets/Consts/Justify.php
index e72dc70..a502e5f 100644
--- a/src/Widgets/Consts/Justify.php
+++ b/src/Widgets/Consts/Justify.php
@@ -1,6 +1,6 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets\Consts;
+namespace Tkui\Widgets\Consts;
 
 /**
  * Values for 'justify' property.
diff --git a/src/Widgets/Consts/Orient.php b/src/Widgets/Consts/Orient.php
index b56e954..8a79be3 100644
--- a/src/Widgets/Consts/Orient.php
+++ b/src/Widgets/Consts/Orient.php
@@ -1,6 +1,6 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets\Consts;
+namespace Tkui\Widgets\Consts;
 
 /**
  * Values for 'orient' property.
diff --git a/src/Widgets/Consts/Relief.php b/src/Widgets/Consts/Relief.php
index 70b0141..332a9d2 100644
--- a/src/Widgets/Consts/Relief.php
+++ b/src/Widgets/Consts/Relief.php
@@ -1,6 +1,6 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets\Consts;
+namespace Tkui\Widgets\Consts;
 
 /**
  * Values for 'relief' property.
diff --git a/src/Widgets/Consts/Validate.php b/src/Widgets/Consts/Validate.php
index 615d304..0dae03b 100644
--- a/src/Widgets/Consts/Validate.php
+++ b/src/Widgets/Consts/Validate.php
@@ -1,6 +1,6 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets\Consts;
+namespace Tkui\Widgets\Consts;
 
 /**
  * Values for 'validate' property.
diff --git a/src/Widgets/Consts/WrapModes.php b/src/Widgets/Consts/WrapModes.php
index ac8ae9a..463e9a5 100644
--- a/src/Widgets/Consts/WrapModes.php
+++ b/src/Widgets/Consts/WrapModes.php
@@ -1,6 +1,6 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets\Consts;
+namespace Tkui\Widgets\Consts;
 
 /**
  * Values for "wrap" property.
diff --git a/src/Widgets/Container.php b/src/Widgets/Container.php
index d84fd25..8bea3e5 100644
--- a/src/Widgets/Container.php
+++ b/src/Widgets/Container.php
@@ -1,12 +1,12 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets;
+namespace Tkui\Widgets;
 
-use PhpGui\Evaluator;
-use PhpGui\Layouts\Grid;
-use PhpGui\Layouts\Pack;
-use PhpGui\Layouts\Place;
-use PhpGui\Windows\Window;
+use Tkui\Evaluator;
+use Tkui\Layouts\Grid;
+use Tkui\Layouts\Pack;
+use Tkui\Layouts\Place;
+use Tkui\Windows\Window;
 
 /**
  * Container widget.
diff --git a/src/Widgets/Entry.php b/src/Widgets/Entry.php
index af8e287..8d2d39f 100644
--- a/src/Widgets/Entry.php
+++ b/src/Widgets/Entry.php
@@ -1,16 +1,16 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets;
-
-use PhpGui\Color;
-use PhpGui\Font;
-use PhpGui\Options;
-use PhpGui\TclTk\Tcl;
-use PhpGui\TclTk\Variable;
-use PhpGui\Widgets\Common\Editable;
-use PhpGui\Widgets\Common\ValueInVariable;
-use PhpGui\Widgets\Consts\Justify;
-use PhpGui\Widgets\Consts\Validate;
+namespace Tkui\Widgets;
+
+use Tkui\Color;
+use Tkui\Font;
+use Tkui\Options;
+use Tkui\TclTk\Tcl;
+use Tkui\TclTk\Variable;
+use Tkui\Widgets\Common\Editable;
+use Tkui\Widgets\Common\ValueInVariable;
+use Tkui\Widgets\Consts\Justify;
+use Tkui\Widgets\Consts\Validate;
 
 /**
  * Implementation of Tk entry widget.
diff --git a/src/Widgets/Exceptions/FontNotSupportedException.php b/src/Widgets/Exceptions/FontNotSupportedException.php
index 2289a29..06ad5ef 100644
--- a/src/Widgets/Exceptions/FontNotSupportedException.php
+++ b/src/Widgets/Exceptions/FontNotSupportedException.php
@@ -1,8 +1,8 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets\Exceptions;
+namespace Tkui\Widgets\Exceptions;
 
-use PhpGui\Widgets\Widget;
+use Tkui\Widgets\Widget;
 
 /**
  * The widget cannot set or update a font.
diff --git a/src/Widgets/Exceptions/TextStyleNotRegisteredException.php b/src/Widgets/Exceptions/TextStyleNotRegisteredException.php
index 7ff491f..3f487c1 100644
--- a/src/Widgets/Exceptions/TextStyleNotRegisteredException.php
+++ b/src/Widgets/Exceptions/TextStyleNotRegisteredException.php
@@ -1,8 +1,8 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets\Exceptions;
+namespace Tkui\Widgets\Exceptions;
 
-use PhpGui\Widgets\Widget;
+use Tkui\Widgets\Widget;
 
 class TextStyleNotRegisteredException extends WidgetException
 {
diff --git a/src/Widgets/Exceptions/WidgetException.php b/src/Widgets/Exceptions/WidgetException.php
index b5ff8eb..14bf8a5 100644
--- a/src/Widgets/Exceptions/WidgetException.php
+++ b/src/Widgets/Exceptions/WidgetException.php
@@ -1,9 +1,9 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets\Exceptions;
+namespace Tkui\Widgets\Exceptions;
 
-use PhpGui\Exceptions\Exception;
-use PhpGui\Widgets\Widget;
+use Tkui\Exceptions\Exception;
+use Tkui\Widgets\Widget;
 
 /**
  * Generic widget exception.
diff --git a/src/Widgets/Frame.php b/src/Widgets/Frame.php
index 57ef779..acf29ff 100644
--- a/src/Widgets/Frame.php
+++ b/src/Widgets/Frame.php
@@ -1,9 +1,9 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets;
+namespace Tkui\Widgets;
 
-use PhpGui\Options;
-use PhpGui\Widgets\Consts\Relief;
+use Tkui\Options;
+use Tkui\Widgets\Consts\Relief;
 
 /**
  * @link https://www.tcl.tk/man/tcl8.6/TkCmd/ttk_frame.htm
diff --git a/src/Widgets/Label.php b/src/Widgets/Label.php
index a84704b..cac0665 100644
--- a/src/Widgets/Label.php
+++ b/src/Widgets/Label.php
@@ -1,16 +1,16 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets;
+namespace Tkui\Widgets;
 
-use PhpGui\Color;
-use PhpGui\Font;
-use PhpGui\Image;
-use PhpGui\Options;
-use PhpGui\TclTk\Variable;
-use PhpGui\Widgets\Common\DetectUnderline;
-use PhpGui\Widgets\Consts\Anchor;
-use PhpGui\Widgets\Consts\Justify;
-use PhpGui\Widgets\Consts\Relief;
+use Tkui\Color;
+use Tkui\Font;
+use Tkui\Image;
+use Tkui\Options;
+use Tkui\TclTk\Variable;
+use Tkui\Widgets\Common\DetectUnderline;
+use Tkui\Widgets\Consts\Anchor;
+use Tkui\Widgets\Consts\Justify;
+use Tkui\Widgets\Consts\Relief;
 
 /**
  * Implementation of Tk label widget.
diff --git a/src/Widgets/LabelFrame.php b/src/Widgets/LabelFrame.php
index 8da7853..885a03f 100644
--- a/src/Widgets/LabelFrame.php
+++ b/src/Widgets/LabelFrame.php
@@ -1,10 +1,10 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets;
+namespace Tkui\Widgets;
 
-use PhpGui\Options;
-use PhpGui\Widgets\Common\DetectUnderline;
-use PhpGui\Widgets\Consts\Anchor;
+use Tkui\Options;
+use Tkui\Widgets\Common\DetectUnderline;
+use Tkui\Widgets\Consts\Anchor;
 
 /**
  * @link https://www.tcl.tk/man/tcl8.6/TkCmd/ttk_labelframe.htm
diff --git a/src/Widgets/Listbox.php b/src/Widgets/Listbox.php
index 5fbff7b..bc5d64a 100644
--- a/src/Widgets/Listbox.php
+++ b/src/Widgets/Listbox.php
@@ -1,12 +1,12 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets;
+namespace Tkui\Widgets;
 
 use InvalidArgumentException;
 use SplObserver;
 use SplSubject;
-use PhpGui\Options;
-use PhpGui\TclTk\Tcl;
+use Tkui\Options;
+use Tkui\TclTk\Tcl;
 
 /**
  * Implementation of Tk listbox widget.
diff --git a/src/Widgets/ListboxItem.php b/src/Widgets/ListboxItem.php
index 0cd7765..1db2d84 100644
--- a/src/Widgets/ListboxItem.php
+++ b/src/Widgets/ListboxItem.php
@@ -1,11 +1,11 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets;
+namespace Tkui\Widgets;
 
-use PhpGui\Color;
+use Tkui\Color;
 use SplObserver;
 use SplSubject;
-use PhpGui\Options;
+use Tkui\Options;
 
 /**
  * Listbox widget item.
diff --git a/src/Widgets/Menu/CommonGroup.php b/src/Widgets/Menu/CommonGroup.php
index b5975bf..aee52f9 100644
--- a/src/Widgets/Menu/CommonGroup.php
+++ b/src/Widgets/Menu/CommonGroup.php
@@ -1,6 +1,6 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets\Menu;
+namespace Tkui\Widgets\Menu;
 
 use ArrayIterator;
 use IteratorAggregate;
diff --git a/src/Widgets/Menu/CommonItem.php b/src/Widgets/Menu/CommonItem.php
index 8e2500c..e4e726d 100644
--- a/src/Widgets/Menu/CommonItem.php
+++ b/src/Widgets/Menu/CommonItem.php
@@ -1,8 +1,8 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets\Menu;
+namespace Tkui\Widgets\Menu;
 
-use PhpGui\Options;
+use Tkui\Options;
 use SplObserver;
 use SplSubject;
 
diff --git a/src/Widgets/Menu/Menu.php b/src/Widgets/Menu/Menu.php
index 11bd902..bb5fe45 100644
--- a/src/Widgets/Menu/Menu.php
+++ b/src/Widgets/Menu/Menu.php
@@ -1,13 +1,13 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets\Menu;
-
-use PhpGui\Color;
-use PhpGui\Options;
-use PhpGui\Widgets\Common\DetectUnderline;
-use PhpGui\Widgets\Container;
-use PhpGui\Widgets\TtkContainer;
-use PhpGui\Widgets\Widget;
+namespace Tkui\Widgets\Menu;
+
+use Tkui\Color;
+use Tkui\Options;
+use Tkui\Widgets\Common\DetectUnderline;
+use Tkui\Widgets\Container;
+use Tkui\Widgets\TtkContainer;
+use Tkui\Widgets\Widget;
 use SplSubject;
 
 /**
diff --git a/src/Widgets/Menu/MenuCheckItem.php b/src/Widgets/Menu/MenuCheckItem.php
index a534e28..d729125 100644
--- a/src/Widgets/Menu/MenuCheckItem.php
+++ b/src/Widgets/Menu/MenuCheckItem.php
@@ -1,12 +1,12 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets\Menu;
+namespace Tkui\Widgets\Menu;
 
-use PhpGui\Options;
-use PhpGui\Exceptions\UninitializedVariableException;
-use PhpGui\TclTk\Variable;
-use PhpGui\Widgets\Common\ValueInVariable;
-use PhpGui\Widgets\TkWidget;
+use Tkui\Options;
+use Tkui\Exceptions\UninitializedVariableException;
+use Tkui\TclTk\Variable;
+use Tkui\Widgets\Common\ValueInVariable;
+use Tkui\Widgets\TkWidget;
 use SplObserver;
 
 /**
diff --git a/src/Widgets/Menu/MenuItem.php b/src/Widgets/Menu/MenuItem.php
index ee86548..504ad16 100644
--- a/src/Widgets/Menu/MenuItem.php
+++ b/src/Widgets/Menu/MenuItem.php
@@ -1,12 +1,12 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets\Menu;
+namespace Tkui\Widgets\Menu;
 
-use PhpGui\Image;
-use PhpGui\Options;
-use PhpGui\Widgets\Common\Clickable;
-use PhpGui\Widgets\Common\DetectUnderline;
-use PhpGui\Widgets\TtkWidget;
+use Tkui\Image;
+use Tkui\Options;
+use Tkui\Widgets\Common\Clickable;
+use Tkui\Widgets\Common\DetectUnderline;
+use Tkui\Widgets\TtkWidget;
 
 /**
  * Implements a simple menu item with a callback.
diff --git a/src/Widgets/Menu/MenuItemGroup.php b/src/Widgets/Menu/MenuItemGroup.php
index b4ff4ef..3358884 100644
--- a/src/Widgets/Menu/MenuItemGroup.php
+++ b/src/Widgets/Menu/MenuItemGroup.php
@@ -1,6 +1,6 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets\Menu;
+namespace Tkui\Widgets\Menu;
 
 /**
  * Aggregates menu items into the group.
diff --git a/src/Widgets/Menu/MenuRadioGroup.php b/src/Widgets/Menu/MenuRadioGroup.php
index 296cac1..7c7766e 100644
--- a/src/Widgets/Menu/MenuRadioGroup.php
+++ b/src/Widgets/Menu/MenuRadioGroup.php
@@ -1,9 +1,9 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets\Menu;
+namespace Tkui\Widgets\Menu;
 
-use PhpGui\Exceptions\UninitializedVariableException;
-use PhpGui\TclTk\Variable;
+use Tkui\Exceptions\UninitializedVariableException;
+use Tkui\TclTk\Variable;
 
 /**
  * Allows to create a group of menu radio items.
diff --git a/src/Widgets/Menu/MenuRadioItem.php b/src/Widgets/Menu/MenuRadioItem.php
index 011b890..6d52ba7 100644
--- a/src/Widgets/Menu/MenuRadioItem.php
+++ b/src/Widgets/Menu/MenuRadioItem.php
@@ -1,12 +1,12 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets\Menu;
+namespace Tkui\Widgets\Menu;
 
-use PhpGui\Exceptions\UninitializedVariableException;
-use PhpGui\Options;
-use PhpGui\TclTk\Variable;
-use PhpGui\Widgets\Common\ValueInVariable;
-use PhpGui\Widgets\TkWidget;
+use Tkui\Exceptions\UninitializedVariableException;
+use Tkui\Options;
+use Tkui\TclTk\Variable;
+use Tkui\Widgets\Common\ValueInVariable;
+use Tkui\Widgets\TkWidget;
 use SplObserver;
 
 /**
diff --git a/src/Widgets/Menu/MenuSeparatorItem.php b/src/Widgets/Menu/MenuSeparatorItem.php
index e8136e2..c3da454 100644
--- a/src/Widgets/Menu/MenuSeparatorItem.php
+++ b/src/Widgets/Menu/MenuSeparatorItem.php
@@ -1,6 +1,6 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets\Menu;
+namespace Tkui\Widgets\Menu;
 
 /**
  * Separator menu item.
diff --git a/src/Widgets/Notebook.php b/src/Widgets/Notebook.php
index 1230f5c..4c12bcd 100644
--- a/src/Widgets/Notebook.php
+++ b/src/Widgets/Notebook.php
@@ -1,11 +1,11 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets;
+namespace Tkui\Widgets;
 
 use InvalidArgumentException;
 use SplObserver;
 use SplSubject;
-use PhpGui\Options;
+use Tkui\Options;
 
 /**
  * Implementation of Ttk notebook widget.
diff --git a/src/Widgets/NotebookTab.php b/src/Widgets/NotebookTab.php
index eaae38c..baf8f4a 100644
--- a/src/Widgets/NotebookTab.php
+++ b/src/Widgets/NotebookTab.php
@@ -1,11 +1,11 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets;
+namespace Tkui\Widgets;
 
 use SplObserver;
 use SplSubject;
-use PhpGui\Options;
-use PhpGui\Widgets\Common\DetectUnderline;
+use Tkui\Options;
+use Tkui\Widgets\Common\DetectUnderline;
 
 /**
  * @property string $state
diff --git a/src/Widgets/PanedWindow.php b/src/Widgets/PanedWindow.php
index ff9f960..e4f1f43 100644
--- a/src/Widgets/PanedWindow.php
+++ b/src/Widgets/PanedWindow.php
@@ -1,10 +1,10 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets;
+namespace Tkui\Widgets;
 
-use PhpGui\Options;
-use PhpGui\Widgets\Consts\Orient;
-use PhpGui\Widgets\Exceptions\WidgetException;
+use Tkui\Options;
+use Tkui\Widgets\Consts\Orient;
+use Tkui\Widgets\Exceptions\WidgetException;
 
 /**
  * @link https://www.tcl.tk/man/tcl8.6/TkCmd/ttk_panedwindow.htm
diff --git a/src/Widgets/RadioGroup.php b/src/Widgets/RadioGroup.php
index 7a5e1ac..eed3f6e 100644
--- a/src/Widgets/RadioGroup.php
+++ b/src/Widgets/RadioGroup.php
@@ -1,11 +1,11 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets;
+namespace Tkui\Widgets;
 
-use PhpGui\TclTk\Variable;
-use PhpGui\Widgets\Buttons\RadioButton;
-use PhpGui\Widgets\Common\Clickable;
-use PhpGui\Widgets\Common\ValueInVariable;
+use Tkui\TclTk\Variable;
+use Tkui\Widgets\Buttons\RadioButton;
+use Tkui\Widgets\Common\Clickable;
+use Tkui\Widgets\Common\ValueInVariable;
 
 // TODO: array iterable
 class RadioGroup extends Frame implements ValueInVariable, Clickable
diff --git a/src/Widgets/Scale.php b/src/Widgets/Scale.php
index 2b81c4c..bb42561 100644
--- a/src/Widgets/Scale.php
+++ b/src/Widgets/Scale.php
@@ -1,11 +1,11 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets;
+namespace Tkui\Widgets;
 
-use PhpGui\Options;
-use PhpGui\TclTk\Variable;
-use PhpGui\Widgets\Common\ValueInVariable;
-use PhpGui\Widgets\Consts\Orient;
+use Tkui\Options;
+use Tkui\TclTk\Variable;
+use Tkui\Widgets\Common\ValueInVariable;
+use Tkui\Widgets\Consts\Orient;
 
 /**
  * Implementation of Tk scale widget.
diff --git a/src/Widgets/ScrollableWidget.php b/src/Widgets/ScrollableWidget.php
index a56507a..d6766c9 100644
--- a/src/Widgets/ScrollableWidget.php
+++ b/src/Widgets/ScrollableWidget.php
@@ -1,6 +1,6 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets;
+namespace Tkui\Widgets;
 
 use InvalidArgumentException;
 
diff --git a/src/Widgets/Scrollbar.php b/src/Widgets/Scrollbar.php
index dcb1f15..ddc4b9d 100644
--- a/src/Widgets/Scrollbar.php
+++ b/src/Widgets/Scrollbar.php
@@ -1,10 +1,10 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets;
+namespace Tkui\Widgets;
 
 use LogicException;
-use PhpGui\Options;
-use PhpGui\Widgets\Consts\Orient;
+use Tkui\Options;
+use Tkui\Widgets\Consts\Orient;
 
 /**
  * Implementation of Tk scrollbar widget.
diff --git a/src/Widgets/Separator.php b/src/Widgets/Separator.php
index 9ebdf0e..3687dd6 100644
--- a/src/Widgets/Separator.php
+++ b/src/Widgets/Separator.php
@@ -1,9 +1,9 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets;
+namespace Tkui\Widgets;
 
-use PhpGui\Options;
-use PhpGui\Widgets\Consts\Orient;
+use Tkui\Options;
+use Tkui\Widgets\Consts\Orient;
 
 /**
  * Implementation of Tk separator widget.
diff --git a/src/Widgets/Sizegrip.php b/src/Widgets/Sizegrip.php
index 5f0e0f6..132bf3a 100644
--- a/src/Widgets/Sizegrip.php
+++ b/src/Widgets/Sizegrip.php
@@ -1,6 +1,6 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets;
+namespace Tkui\Widgets;
 
 /**
  * Implementation of Ttk sizegrip widget.
diff --git a/src/Widgets/Spinbox.php b/src/Widgets/Spinbox.php
index 54ab040..e870160 100644
--- a/src/Widgets/Spinbox.php
+++ b/src/Widgets/Spinbox.php
@@ -1,10 +1,10 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets;
+namespace Tkui\Widgets;
 
-use PhpGui\Options;
-use PhpGui\TclTk\Variable;
-use PhpGui\Widgets\Common\ValueInVariable;
+use Tkui\Options;
+use Tkui\TclTk\Variable;
+use Tkui\Widgets\Common\ValueInVariable;
 
 /**
  * Implementation of Ttk spinbox widget.
diff --git a/src/Widgets/Text/EditStack.php b/src/Widgets/Text/EditStack.php
index 1b344f5..4c32657 100644
--- a/src/Widgets/Text/EditStack.php
+++ b/src/Widgets/Text/EditStack.php
@@ -1,6 +1,6 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets\Text;
+namespace Tkui\Widgets\Text;
 
 /**
  * EditStack provides undo/redo operations and checking its state.
diff --git a/src/Widgets/Text/EmbeddedImage.php b/src/Widgets/Text/EmbeddedImage.php
index b50aa1b..783d707 100644
--- a/src/Widgets/Text/EmbeddedImage.php
+++ b/src/Widgets/Text/EmbeddedImage.php
@@ -1,9 +1,9 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets\Text;
+namespace Tkui\Widgets\Text;
 
-use PhpGui\Image;
-use PhpGui\Options;
+use Tkui\Image;
+use Tkui\Options;
 
 /**
  * @property string $align
diff --git a/src/Widgets/Text/Range.php b/src/Widgets/Text/Range.php
index 9c5716a..90dddda 100644
--- a/src/Widgets/Text/Range.php
+++ b/src/Widgets/Text/Range.php
@@ -1,6 +1,6 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets\Text;
+namespace Tkui\Widgets\Text;
 
 /**
  * A range of text content.
diff --git a/src/Widgets/Text/SearchOptions.php b/src/Widgets/Text/SearchOptions.php
index 6d266cf..33c46ce 100644
--- a/src/Widgets/Text/SearchOptions.php
+++ b/src/Widgets/Text/SearchOptions.php
@@ -1,6 +1,6 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets\Text;
+namespace Tkui\Widgets\Text;
 
 use InvalidArgumentException;
 
diff --git a/src/Widgets/Text/Selection.php b/src/Widgets/Text/Selection.php
index e05bdbc..c969d47 100644
--- a/src/Widgets/Text/Selection.php
+++ b/src/Widgets/Text/Selection.php
@@ -1,6 +1,6 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets\Text;
+namespace Tkui\Widgets\Text;
 
 /**
  * The text selection.
diff --git a/src/Widgets/Text/Text.php b/src/Widgets/Text/Text.php
index 1613a1b..85de874 100644
--- a/src/Widgets/Text/Text.php
+++ b/src/Widgets/Text/Text.php
@@ -1,16 +1,16 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets\Text;
-
-use PhpGui\Font;
-use PhpGui\Image;
-use PhpGui\Options;
-use PhpGui\Widgets\Common\Editable;
-use PhpGui\Widgets\Consts\WrapModes;
-use PhpGui\Widgets\Container;
-use PhpGui\Widgets\Exceptions\TextStyleNotRegisteredException;
-use PhpGui\Widgets\Exceptions\WidgetException;
-use PhpGui\Widgets\ScrollableWidget;
+namespace Tkui\Widgets\Text;
+
+use Tkui\Font;
+use Tkui\Image;
+use Tkui\Options;
+use Tkui\Widgets\Common\Editable;
+use Tkui\Widgets\Consts\WrapModes;
+use Tkui\Widgets\Container;
+use Tkui\Widgets\Exceptions\TextStyleNotRegisteredException;
+use Tkui\Widgets\Exceptions\WidgetException;
+use Tkui\Widgets\ScrollableWidget;
 
 /**
  * Implementation of Tk text widget.
diff --git a/src/Widgets/Text/TextApiMethodBridge.php b/src/Widgets/Text/TextApiMethodBridge.php
index 083db79..a426f25 100644
--- a/src/Widgets/Text/TextApiMethodBridge.php
+++ b/src/Widgets/Text/TextApiMethodBridge.php
@@ -1,6 +1,6 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets\Text;
+namespace Tkui\Widgets\Text;
 
 /**
  * Provides the bridge method to text api.
diff --git a/src/Widgets/Text/TextIndex.php b/src/Widgets/Text/TextIndex.php
index 8a6cce0..3787c0c 100644
--- a/src/Widgets/Text/TextIndex.php
+++ b/src/Widgets/Text/TextIndex.php
@@ -1,6 +1,6 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets\Text;
+namespace Tkui\Widgets\Text;
 
 use Exception;
 
diff --git a/src/Widgets/Text/TextStyle.php b/src/Widgets/Text/TextStyle.php
index 1742a25..6ec9794 100644
--- a/src/Widgets/Text/TextStyle.php
+++ b/src/Widgets/Text/TextStyle.php
@@ -1,13 +1,13 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets\Text;
+namespace Tkui\Widgets\Text;
 
-use PhpGui\Color;
-use PhpGui\Font;
-use PhpGui\Options;
-use PhpGui\Widgets\Consts\Justify;
-use PhpGui\Widgets\Consts\Relief;
-use PhpGui\Widgets\Consts\WrapModes;
+use Tkui\Color;
+use Tkui\Font;
+use Tkui\Options;
+use Tkui\Widgets\Consts\Justify;
+use Tkui\Widgets\Consts\Relief;
+use Tkui\Widgets\Consts\WrapModes;
 
 /**
  * Text style.
diff --git a/src/Widgets/TkWidget.php b/src/Widgets/TkWidget.php
index 7db6714..06ce80e 100644
--- a/src/Widgets/TkWidget.php
+++ b/src/Widgets/TkWidget.php
@@ -1,9 +1,9 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets;
+namespace Tkui\Widgets;
 
-use PhpGui\Evaluator;
-use PhpGui\Options;
+use Tkui\Evaluator;
+use Tkui\Options;
 use SplObserver;
 use SplSubject;
 
diff --git a/src/Widgets/TtkContainer.php b/src/Widgets/TtkContainer.php
index 45f0c7d..bc9fb10 100644
--- a/src/Widgets/TtkContainer.php
+++ b/src/Widgets/TtkContainer.php
@@ -1,12 +1,12 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets;
+namespace Tkui\Widgets;
 
-use PhpGui\Evaluator;
-use PhpGui\Layouts\Grid;
-use PhpGui\Layouts\Pack;
-use PhpGui\Layouts\Place;
-use PhpGui\Windows\Window;
+use Tkui\Evaluator;
+use Tkui\Layouts\Grid;
+use Tkui\Layouts\Pack;
+use Tkui\Layouts\Place;
+use Tkui\Windows\Window;
 
 abstract class TtkContainer extends TtkWidget implements Container
 {
diff --git a/src/Widgets/TtkWidget.php b/src/Widgets/TtkWidget.php
index d6be35d..bafb355 100644
--- a/src/Widgets/TtkWidget.php
+++ b/src/Widgets/TtkWidget.php
@@ -1,11 +1,11 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets;
+namespace Tkui\Widgets;
 
-use PhpGui\Font;
-use PhpGui\Image;
-use PhpGui\Options;
-use PhpGui\Widgets\Exceptions\FontNotSupportedException;
+use Tkui\Font;
+use Tkui\Image;
+use Tkui\Options;
+use Tkui\Widgets\Exceptions\FontNotSupportedException;
 use SplSubject;
 
 /**
diff --git a/src/Widgets/Widget.php b/src/Widgets/Widget.php
index b474888..4d7c2f0 100644
--- a/src/Widgets/Widget.php
+++ b/src/Widgets/Widget.php
@@ -1,8 +1,8 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets;
+namespace Tkui\Widgets;
 
-use PhpGui\Options;
+use Tkui\Options;
 
 /**
  * Basic widget.
diff --git a/src/Widgets/WidgetOptions.php b/src/Widgets/WidgetOptions.php
index fb7a874..db6c537 100644
--- a/src/Widgets/WidgetOptions.php
+++ b/src/Widgets/WidgetOptions.php
@@ -1,8 +1,8 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Widgets;
+namespace Tkui\Widgets;
 
-use PhpGui\Options;
+use Tkui\Options;
 
 /**
  * Common Tk widget options.
diff --git a/src/WindowManager.php b/src/WindowManager.php
index f8501bb..58a4ea9 100644
--- a/src/WindowManager.php
+++ b/src/WindowManager.php
@@ -1,6 +1,6 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui;
+namespace Tkui;
 
 /**
  * Window Manager performs operation against the current window.
diff --git a/src/Windows/BaseWindow.php b/src/Windows/BaseWindow.php
index 781bbf6..3a4bdfb 100644
--- a/src/Windows/BaseWindow.php
+++ b/src/Windows/BaseWindow.php
@@ -1,17 +1,17 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Windows;
-
-use PhpGui\Layouts\Grid;
-use PhpGui\Layouts\LayoutManager;
-use PhpGui\Layouts\Pack;
-use PhpGui\Layouts\Place;
-use PhpGui\Options;
-use PhpGui\TclTk\TkWindowManager;
-use PhpGui\Widgets\Container;
-use PhpGui\Widgets\Menu\Menu;
-use PhpGui\Widgets\Widget;
-use PhpGui\WindowManager;
+namespace Tkui\Windows;
+
+use Tkui\Layouts\Grid;
+use Tkui\Layouts\LayoutManager;
+use Tkui\Layouts\Pack;
+use Tkui\Layouts\Place;
+use Tkui\Options;
+use Tkui\TclTk\TkWindowManager;
+use Tkui\Widgets\Container;
+use Tkui\Widgets\Menu\Menu;
+use Tkui\Widgets\Widget;
+use Tkui\WindowManager;
 
 /**
  * Shares the features for window implementations.
diff --git a/src/Windows/ChildWindow.php b/src/Windows/ChildWindow.php
index a7f6420..ab920af 100644
--- a/src/Windows/ChildWindow.php
+++ b/src/Windows/ChildWindow.php
@@ -1,10 +1,10 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Windows;
+namespace Tkui\Windows;
 
-use PhpGui\Evaluator;
-use PhpGui\Widgets\Container;
-use PhpGui\Widgets\Widget;
+use Tkui\Evaluator;
+use Tkui\Widgets\Container;
+use Tkui\Widgets\Widget;
 
 /**
  * Child window implementation.
diff --git a/src/Windows/MainWindow.php b/src/Windows/MainWindow.php
index 6fc4dad..567057b 100644
--- a/src/Windows/MainWindow.php
+++ b/src/Windows/MainWindow.php
@@ -1,11 +1,11 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Windows;
+namespace Tkui\Windows;
 
-use PhpGui\Application;
-use PhpGui\Evaluator;
-use PhpGui\Widgets\Container;
-use PhpGui\Widgets\Widget;
+use Tkui\Application;
+use Tkui\Evaluator;
+use Tkui\Widgets\Container;
+use Tkui\Widgets\Widget;
 
 /**
  * The main application window implementation.
diff --git a/src/Windows/ModalWindow.php b/src/Windows/ModalWindow.php
index eddebbb..a5f0e4d 100644
--- a/src/Windows/ModalWindow.php
+++ b/src/Windows/ModalWindow.php
@@ -1,6 +1,6 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Windows;
+namespace Tkui\Windows;
 
 /**
  * Windows that can be shown as modals.
diff --git a/src/Windows/Window.php b/src/Windows/Window.php
index deab060..23af172 100644
--- a/src/Windows/Window.php
+++ b/src/Windows/Window.php
@@ -1,10 +1,10 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Windows;
+namespace Tkui\Windows;
 
-use PhpGui\Widgets\Container;
-use PhpGui\Widgets\Menu\Menu;
-use PhpGui\WindowManager;
+use Tkui\Widgets\Container;
+use Tkui\Widgets\Menu\Menu;
+use Tkui\WindowManager;
 
 /**
  * The application window.
diff --git a/tests/App/BindingsTest.php b/tests/App/BindingsTest.php
index d6aa0fc..8224fec 100644
--- a/tests/App/BindingsTest.php
+++ b/tests/App/BindingsTest.php
@@ -1,11 +1,11 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Tests\App;
+namespace Tkui\Tests\App;
 
-use PhpGui\TclTk\Interp;
-use PhpGui\Tests\TestCase;
-use PhpGui\TclTk\TkBindings;
-use PhpGui\Widgets\Buttons\Button;
+use Tkui\TclTk\Interp;
+use Tkui\Tests\TestCase;
+use Tkui\TclTk\TkBindings;
+use Tkui\Widgets\Buttons\Button;
 
 class BindingsTest extends TestCase
 {
diff --git a/tests/App/ColorTest.php b/tests/App/ColorTest.php
index 95f0e83..d9e3528 100644
--- a/tests/App/ColorTest.php
+++ b/tests/App/ColorTest.php
@@ -1,9 +1,9 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Tests;
+namespace Tkui\Tests;
 
 use InvalidArgumentException;
-use PhpGui\Color;
+use Tkui\Color;
 
 class ColorTest extends TestCase
 {
diff --git a/tests/App/FontTest.php b/tests/App/FontTest.php
index 1a4e24b..6aea771 100644
--- a/tests/App/FontTest.php
+++ b/tests/App/FontTest.php
@@ -1,10 +1,10 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Tests\App;
+namespace Tkui\Tests\App;
 
 use InvalidArgumentException;
-use PhpGui\Font;
-use PhpGui\Tests\TestCase;
+use Tkui\Font;
+use Tkui\Tests\TestCase;
 use SplObserver;
 
 class FontTest extends TestCase
diff --git a/tests/App/TkFontTest.php b/tests/App/TkFontTest.php
index 8d2b5b5..74583e9 100644
--- a/tests/App/TkFontTest.php
+++ b/tests/App/TkFontTest.php
@@ -1,9 +1,9 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Tests\App;
+namespace Tkui\Tests\App;
 
-use PhpGui\TclTk\TkFont;
-use PhpGui\Tests\TestCase;
+use Tkui\TclTk\TkFont;
+use Tkui\Tests\TestCase;
 
 class TkFontTest extends TestCase
 {
diff --git a/tests/App/TkImageFactoryTest.php b/tests/App/TkImageFactoryTest.php
index eb41659..5ac129a 100644
--- a/tests/App/TkImageFactoryTest.php
+++ b/tests/App/TkImageFactoryTest.php
@@ -1,10 +1,10 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Tests\App;
+namespace Tkui\Tests\App;
 
-use PhpGui\TclTk\Interp;
-use PhpGui\TclTk\TkImageFactory;
-use PhpGui\Tests\TestCase;
+use Tkui\TclTk\Interp;
+use Tkui\TclTk\TkImageFactory;
+use Tkui\Tests\TestCase;
 use PHPUnit\Framework\MockObject\MockObject;
 
 class TkImageFactoryTest extends TestCase
diff --git a/tests/App/WindowManagerTest.php b/tests/App/WindowManagerTest.php
index ef7adfe..1a92245 100644
--- a/tests/App/WindowManagerTest.php
+++ b/tests/App/WindowManagerTest.php
@@ -1,9 +1,9 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Tests\App;
+namespace Tkui\Tests\App;
 
-use PhpGui\Tests\TestCase;
-use PhpGui\Windows\MainWindow;
+use Tkui\Tests\TestCase;
+use Tkui\Windows\MainWindow;
 
 class WindowManagerTest extends TestCase
 {
diff --git a/tests/Dialogs/ColorDialogTest.php b/tests/Dialogs/ColorDialogTest.php
index 6b4bdea..b87dda6 100644
--- a/tests/Dialogs/ColorDialogTest.php
+++ b/tests/Dialogs/ColorDialogTest.php
@@ -1,9 +1,9 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Tests\Dialogs;
+namespace Tkui\Tests\Dialogs;
 
-use PhpGui\Dialogs\ColorDialog;
-use PhpGui\Tests\TestCase;
+use Tkui\Dialogs\ColorDialog;
+use Tkui\Tests\TestCase;
 
 class ColorDialogTest extends TestCase
 {
diff --git a/tests/Dialogs/DirectoryDialogTest.php b/tests/Dialogs/DirectoryDialogTest.php
index 3bd52dc..f7ec663 100644
--- a/tests/Dialogs/DirectoryDialogTest.php
+++ b/tests/Dialogs/DirectoryDialogTest.php
@@ -1,9 +1,9 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Tests\Dialogs;
+namespace Tkui\Tests\Dialogs;
 
-use PhpGui\Dialogs\DirectoryDialog;
-use PhpGui\Tests\TestCase;
+use Tkui\Dialogs\DirectoryDialog;
+use Tkui\Tests\TestCase;
 
 class DirectoryDialogTest extends TestCase
 {
diff --git a/tests/Dialogs/FontDialogTest.php b/tests/Dialogs/FontDialogTest.php
index b9157e8..ec65634 100644
--- a/tests/Dialogs/FontDialogTest.php
+++ b/tests/Dialogs/FontDialogTest.php
@@ -1,10 +1,10 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Tests\Dialogs;
+namespace Tkui\Tests\Dialogs;
 
-use PhpGui\Dialogs\FontDialog;
-use PhpGui\FontManager;
-use PhpGui\Tests\TestCase;
+use Tkui\Dialogs\FontDialog;
+use Tkui\FontManager;
+use Tkui\Tests\TestCase;
 
 class FontDialogTest extends TestCase
 {
diff --git a/tests/Dialogs/MessageBoxTest.php b/tests/Dialogs/MessageBoxTest.php
index 3010f19..125dc2a 100644
--- a/tests/Dialogs/MessageBoxTest.php
+++ b/tests/Dialogs/MessageBoxTest.php
@@ -1,9 +1,9 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Tests\Dialogs;
+namespace Tkui\Tests\Dialogs;
 
-use PhpGui\Dialogs\MessageBox;
-use PhpGui\Tests\TestCase;
+use Tkui\Dialogs\MessageBox;
+use Tkui\Tests\TestCase;
 
 class MessageBoxTest extends TestCase
 {
diff --git a/tests/Dialogs/OpenFileDialogTest.php b/tests/Dialogs/OpenFileDialogTest.php
index 128d036..dd6b509 100644
--- a/tests/Dialogs/OpenFileDialogTest.php
+++ b/tests/Dialogs/OpenFileDialogTest.php
@@ -1,9 +1,9 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Tests\Dialogs;
+namespace Tkui\Tests\Dialogs;
 
-use PhpGui\Dialogs\OpenFileDialog;
-use PhpGui\Tests\TestCase;
+use Tkui\Dialogs\OpenFileDialog;
+use Tkui\Tests\TestCase;
 
 class OpenFileDialogTest extends TestCase
 {
diff --git a/tests/Options/OptionsTclStringTest.php b/tests/Options/OptionsTclStringTest.php
index 8f068e8..e89b75f 100644
--- a/tests/Options/OptionsTclStringTest.php
+++ b/tests/Options/OptionsTclStringTest.php
@@ -1,9 +1,9 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Tests\Unit;
+namespace Tkui\Tests\Unit;
 
-use PhpGui\Options;
-use PhpGui\Tests\TestCase;
+use Tkui\Options;
+use Tkui\Tests\TestCase;
 
 class OptionsTclStringTest extends TestCase
 {
diff --git a/tests/Options/OptionsTest.php b/tests/Options/OptionsTest.php
index f6f59e7..6e351ab 100644
--- a/tests/Options/OptionsTest.php
+++ b/tests/Options/OptionsTest.php
@@ -1,10 +1,10 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Tests\Unit;
+namespace Tkui\Tests\Unit;
 
 use InvalidArgumentException;
-use PhpGui\Options;
-use PhpGui\Tests\TestCase;
+use Tkui\Options;
+use Tkui\Tests\TestCase;
 
 class OptionsTest extends TestCase
 {
diff --git a/tests/Tcl/EvalArgsTest.php b/tests/Tcl/EvalArgsTest.php
index 72bdb4b..b39f5b3 100644
--- a/tests/Tcl/EvalArgsTest.php
+++ b/tests/Tcl/EvalArgsTest.php
@@ -1,11 +1,11 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Tests\Tcl;
+namespace Tkui\Tests\Tcl;
 
-use PhpGui\TclTk\Interp;
-use PhpGui\TclTk\Tk;
-use PhpGui\TclTk\TkApplication;
-use PhpGui\Tests\TestCase;
+use Tkui\TclTk\Interp;
+use Tkui\TclTk\Tk;
+use Tkui\TclTk\TkApplication;
+use Tkui\Tests\TestCase;
 use PHPUnit\Framework\MockObject\MockObject;
 
 class EvalArgsTest extends TestCase
diff --git a/tests/Tcl/SetGetVarTest.php b/tests/Tcl/SetGetVarTest.php
index c4b9cb6..47710ef 100644
--- a/tests/Tcl/SetGetVarTest.php
+++ b/tests/Tcl/SetGetVarTest.php
@@ -1,10 +1,10 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Tests\Tcl;
+namespace Tkui\Tests\Tcl;
 
-use PhpGui\TclTk\Exceptions\TclInterpException;
-use PhpGui\Tests\TclInterp;
-use PhpGui\Tests\TestCase;
+use Tkui\TclTk\Exceptions\TclInterpException;
+use Tkui\Tests\TclInterp;
+use Tkui\Tests\TestCase;
 
 class SetGetVarTest extends TestCase
 {
diff --git a/tests/Tcl/StringTest.php b/tests/Tcl/StringTest.php
index 6ede12d..8d1e20e 100644
--- a/tests/Tcl/StringTest.php
+++ b/tests/Tcl/StringTest.php
@@ -1,9 +1,9 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Tests\Tcl;
+namespace Tkui\Tests\Tcl;
 
-use PhpGui\TclTk\Tcl;
-use PhpGui\Tests\TestCase;
+use Tkui\TclTk\Tcl;
+use Tkui\Tests\TestCase;
 
 class StringTest extends TestCase
 {
diff --git a/tests/Tcl/TclObjTest.php b/tests/Tcl/TclObjTest.php
index d076094..3ff60f1 100644
--- a/tests/Tcl/TclObjTest.php
+++ b/tests/Tcl/TclObjTest.php
@@ -1,10 +1,10 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Tests\Tcl;
+namespace Tkui\Tests\Tcl;
 
-use PhpGui\TclTk\Exceptions\TclInterpException;
-use PhpGui\Tests\TclInterp;
-use PhpGui\Tests\TestCase;
+use Tkui\TclTk\Exceptions\TclInterpException;
+use Tkui\Tests\TclInterp;
+use Tkui\Tests\TestCase;
 
 class TclObjTest extends TestCase
 {
diff --git a/tests/Tcl/VariableTest.php b/tests/Tcl/VariableTest.php
index 1e26a54..f897147 100644
--- a/tests/Tcl/VariableTest.php
+++ b/tests/Tcl/VariableTest.php
@@ -1,10 +1,10 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Tests\Tcl;
+namespace Tkui\Tests\Tcl;
 
-use PhpGui\TclTk\Exceptions\TclInterpException;
-use PhpGui\Tests\TclInterp;
-use PhpGui\Tests\TestCase;
+use Tkui\TclTk\Exceptions\TclInterpException;
+use Tkui\Tests\TclInterp;
+use Tkui\Tests\TestCase;
 
 class VariableTest extends TestCase
 {
diff --git a/tests/TclInterp.php b/tests/TclInterp.php
index fb19772..d8feb9f 100644
--- a/tests/TclInterp.php
+++ b/tests/TclInterp.php
@@ -1,12 +1,12 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Tests;
+namespace Tkui\Tests;
 
-use PhpGui\DotEnv;
-use PhpGui\System\FFILoader;
-use PhpGui\System\OS;
-use PhpGui\TclTk\Interp;
-use PhpGui\TclTk\Tcl;
+use Tkui\DotEnv;
+use Tkui\System\FFILoader;
+use Tkui\System\OS;
+use Tkui\TclTk\Interp;
+use Tkui\TclTk\Tcl;
 use RuntimeException;
 
 trait TclInterp
diff --git a/tests/TestCase.php b/tests/TestCase.php
index 5f37438..73670bb 100644
--- a/tests/TestCase.php
+++ b/tests/TestCase.php
@@ -1,14 +1,14 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Tests;
+namespace Tkui\Tests;
 
 use PHPUnit\Framework\MockObject\MockObject;
 use PHPUnit\Framework\MockObject\Stub;
 use PHPUnit\Framework\TestCase as FrameworkTestCase;
-use PhpGui\Application;
-use PhpGui\Evaluator;
-use PhpGui\Widgets\Widget;
-use PhpGui\Windows\Window;
+use Tkui\Application;
+use Tkui\Evaluator;
+use Tkui\Widgets\Widget;
+use Tkui\Windows\Window;
 
 class TestCase extends FrameworkTestCase
 {
diff --git a/tests/Widgets/ButtonTest.php b/tests/Widgets/ButtonTest.php
index 6e83e56..20f3306 100644
--- a/tests/Widgets/ButtonTest.php
+++ b/tests/Widgets/ButtonTest.php
@@ -1,12 +1,12 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Tests\Widgets;
+namespace Tkui\Tests\Widgets;
 
 use InvalidArgumentException;
 use PHPUnit\Framework\MockObject\MockObject;
-use PhpGui\Tests\TestCase;
-use PhpGui\Widgets\Buttons\Button;
-use PhpGui\Windows\Window;
+use Tkui\Tests\TestCase;
+use Tkui\Widgets\Buttons\Button;
+use Tkui\Windows\Window;
 
 class ButtonTest extends TestCase
 {
diff --git a/tests/Widgets/CheckButtonTest.php b/tests/Widgets/CheckButtonTest.php
index 16fd929..e1f36d1 100644
--- a/tests/Widgets/CheckButtonTest.php
+++ b/tests/Widgets/CheckButtonTest.php
@@ -1,10 +1,10 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Tests\Widgets;
+namespace Tkui\Tests\Widgets;
 
-use PhpGui\Tests\TestCase;
-use PhpGui\TclTk\Variable;
-use PhpGui\Widgets\Buttons\CheckButton;
+use Tkui\Tests\TestCase;
+use Tkui\TclTk\Variable;
+use Tkui\Widgets\Buttons\CheckButton;
 
 class CheckButtonTest extends TestCase
 {
diff --git a/tests/Widgets/EntryTest.php b/tests/Widgets/EntryTest.php
index 10e714a..f41679f 100644
--- a/tests/Widgets/EntryTest.php
+++ b/tests/Widgets/EntryTest.php
@@ -1,13 +1,13 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Tests\Widgets;
+namespace Tkui\Tests\Widgets;
 
-use PhpGui\TclTk\TkFont;
+use Tkui\TclTk\TkFont;
 use PHPUnit\Framework\MockObject\Stub\Stub;
-use PhpGui\Tests\TestCase;
-use PhpGui\TclTk\Variable;
-use PhpGui\Widgets\Entry;
-use PhpGui\Widgets\Widget;
+use Tkui\Tests\TestCase;
+use Tkui\TclTk\Variable;
+use Tkui\Widgets\Entry;
+use Tkui\Widgets\Widget;
 
 class EntryTest extends TestCase
 {
diff --git a/tests/Widgets/FrameTest.php b/tests/Widgets/FrameTest.php
index 3368967..d290c0f 100644
--- a/tests/Widgets/FrameTest.php
+++ b/tests/Widgets/FrameTest.php
@@ -1,9 +1,9 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Tests\Widgets;
+namespace Tkui\Tests\Widgets;
 
-use PhpGui\Tests\TestCase;
-use PhpGui\Widgets\Frame;
+use Tkui\Tests\TestCase;
+use Tkui\Widgets\Frame;
 
 class FrameTest extends TestCase
 {
diff --git a/tests/Widgets/LabelFrameTest.php b/tests/Widgets/LabelFrameTest.php
index 990d472..69d7c2c 100644
--- a/tests/Widgets/LabelFrameTest.php
+++ b/tests/Widgets/LabelFrameTest.php
@@ -1,9 +1,9 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Tests\Widgets;
+namespace Tkui\Tests\Widgets;
 
-use PhpGui\Tests\TestCase;
-use PhpGui\Widgets\LabelFrame;
+use Tkui\Tests\TestCase;
+use Tkui\Widgets\LabelFrame;
 
 class LabelFrameTest extends TestCase
 {
diff --git a/tests/Widgets/LabelTest.php b/tests/Widgets/LabelTest.php
index 2bcd838..38cd9b4 100644
--- a/tests/Widgets/LabelTest.php
+++ b/tests/Widgets/LabelTest.php
@@ -1,10 +1,10 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Tests\Widgets;
+namespace Tkui\Tests\Widgets;
 
-use PhpGui\TclTk\TkFont;
-use PhpGui\Tests\TestCase;
-use PhpGui\Widgets\Label;
+use Tkui\TclTk\TkFont;
+use Tkui\Tests\TestCase;
+use Tkui\Widgets\Label;
 
 class LabelTest extends TestCase
 {
diff --git a/tests/Widgets/ListboxItemTest.php b/tests/Widgets/ListboxItemTest.php
index 74acb86..646d5fd 100644
--- a/tests/Widgets/ListboxItemTest.php
+++ b/tests/Widgets/ListboxItemTest.php
@@ -1,11 +1,11 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Tests\Widgets;
+namespace Tkui\Tests\Widgets;
 
 use PHPUnit\Framework\MockObject\MockObject;
-use PhpGui\Tests\TestCase;
-use PhpGui\Widgets\Listbox;
-use PhpGui\Widgets\ListboxItem;
+use Tkui\Tests\TestCase;
+use Tkui\Widgets\Listbox;
+use Tkui\Widgets\ListboxItem;
 
 class ListboxItemTest extends TestCase
 {
diff --git a/tests/Widgets/ListboxTest.php b/tests/Widgets/ListboxTest.php
index 488bac5..518af65 100644
--- a/tests/Widgets/ListboxTest.php
+++ b/tests/Widgets/ListboxTest.php
@@ -1,13 +1,13 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Tests\Widgets;
+namespace Tkui\Tests\Widgets;
 
 use InvalidArgumentException;
 use PHPUnit\Framework\MockObject\MockObject;
-use PhpGui\Tests\TestCase;
-use PhpGui\Widgets\Listbox;
-use PhpGui\Widgets\ListboxItem;
-use PhpGui\Widgets\Scrollbar;
+use Tkui\Tests\TestCase;
+use Tkui\Widgets\Listbox;
+use Tkui\Widgets\ListboxItem;
+use Tkui\Widgets\Scrollbar;
 
 class ListboxTest extends TestCase
 {
diff --git a/tests/Widgets/MenuButtonTest.php b/tests/Widgets/MenuButtonTest.php
index 18bf739..5ad2e99 100644
--- a/tests/Widgets/MenuButtonTest.php
+++ b/tests/Widgets/MenuButtonTest.php
@@ -1,11 +1,11 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Tests\Widgets;
+namespace Tkui\Tests\Widgets;
 
-use PhpGui\Tests\TestCase;
-use PhpGui\Widgets\Buttons\MenuButton;
-use PhpGui\Widgets\Menu\Menu;
-use PhpGui\Widgets\Menu\MenuItem;
+use Tkui\Tests\TestCase;
+use Tkui\Widgets\Buttons\MenuButton;
+use Tkui\Widgets\Menu\Menu;
+use Tkui\Widgets\Menu\MenuItem;
 
 class MenuButtonTest extends TestCase
 {
diff --git a/tests/Widgets/MenuTest.php b/tests/Widgets/MenuTest.php
index b2cc752..6003ed9 100644
--- a/tests/Widgets/MenuTest.php
+++ b/tests/Widgets/MenuTest.php
@@ -1,12 +1,12 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Tests\Widgets;
+namespace Tkui\Tests\Widgets;
 
-use PhpGui\Tests\TestCase;
-use PhpGui\Widgets\Menu\Menu;
-use PhpGui\Widgets\Menu\MenuCheckItem;
-use PhpGui\Widgets\Menu\MenuItem;
-use PhpGui\Widgets\Menu\MenuRadioItem;
+use Tkui\Tests\TestCase;
+use Tkui\Widgets\Menu\Menu;
+use Tkui\Widgets\Menu\MenuCheckItem;
+use Tkui\Widgets\Menu\MenuItem;
+use Tkui\Widgets\Menu\MenuRadioItem;
 
 class MenuTest extends TestCase
 {
diff --git a/tests/Widgets/NotebookTest.php b/tests/Widgets/NotebookTest.php
index 7bbf545..beb5ef2 100644
--- a/tests/Widgets/NotebookTest.php
+++ b/tests/Widgets/NotebookTest.php
@@ -1,11 +1,11 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Tests\Widgets;
+namespace Tkui\Tests\Widgets;
 
-use PhpGui\Tests\TestCase;
-use PhpGui\Widgets\Frame;
-use PhpGui\Widgets\Notebook;
-use PhpGui\Widgets\NotebookTab;
+use Tkui\Tests\TestCase;
+use Tkui\Widgets\Frame;
+use Tkui\Widgets\Notebook;
+use Tkui\Widgets\NotebookTab;
 
 class NotebookTest extends TestCase
 {
diff --git a/tests/Widgets/PanedWindowTest.php b/tests/Widgets/PanedWindowTest.php
index 212e6e8..1be5bac 100644
--- a/tests/Widgets/PanedWindowTest.php
+++ b/tests/Widgets/PanedWindowTest.php
@@ -1,9 +1,9 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Tests\Widgets;
+namespace Tkui\Tests\Widgets;
 
-use PhpGui\Tests\TestCase;
-use PhpGui\Widgets\PanedWindow;
+use Tkui\Tests\TestCase;
+use Tkui\Widgets\PanedWindow;
 
 class PanedWindowTest extends TestCase
 {
diff --git a/tests/Widgets/RadioButtonTest.php b/tests/Widgets/RadioButtonTest.php
index 2070e8c..322c3b6 100644
--- a/tests/Widgets/RadioButtonTest.php
+++ b/tests/Widgets/RadioButtonTest.php
@@ -1,10 +1,10 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Tests\Widgets;
+namespace Tkui\Tests\Widgets;
 
-use PhpGui\Tests\TestCase;
-use PhpGui\TclTk\Variable;
-use PhpGui\Widgets\Buttons\RadioButton;
+use Tkui\Tests\TestCase;
+use Tkui\TclTk\Variable;
+use Tkui\Widgets\Buttons\RadioButton;
 
 class RadioButtonTest extends TestCase
 {
diff --git a/tests/Widgets/ScaleTest.php b/tests/Widgets/ScaleTest.php
index 09f6dc8..704d1d6 100644
--- a/tests/Widgets/ScaleTest.php
+++ b/tests/Widgets/ScaleTest.php
@@ -1,9 +1,9 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Tests\Widgets;
+namespace Tkui\Tests\Widgets;
 
-use PhpGui\Tests\TestCase;
-use PhpGui\Widgets\Scale;
+use Tkui\Tests\TestCase;
+use Tkui\Widgets\Scale;
 
 class ScaleTest extends TestCase
 {
diff --git a/tests/Widgets/ScrollbarTest.php b/tests/Widgets/ScrollbarTest.php
index f73bda2..9c27c2a 100644
--- a/tests/Widgets/ScrollbarTest.php
+++ b/tests/Widgets/ScrollbarTest.php
@@ -1,11 +1,11 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Tests\Widgets;
+namespace Tkui\Tests\Widgets;
 
 use PHPUnit\Framework\MockObject\Stub;
-use PhpGui\Tests\TestCase;
-use PhpGui\Widgets\ScrollableWidget;
-use PhpGui\Widgets\Scrollbar;
+use Tkui\Tests\TestCase;
+use Tkui\Widgets\ScrollableWidget;
+use Tkui\Widgets\Scrollbar;
 
 class ScrollbarTest extends TestCase
 {
diff --git a/tests/Widgets/SeparatorTest.php b/tests/Widgets/SeparatorTest.php
index 8e92224..ea8bc43 100644
--- a/tests/Widgets/SeparatorTest.php
+++ b/tests/Widgets/SeparatorTest.php
@@ -1,9 +1,9 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Tests\Widgets;
+namespace Tkui\Tests\Widgets;
 
-use PhpGui\Tests\TestCase;
-use PhpGui\Widgets\Separator;
+use Tkui\Tests\TestCase;
+use Tkui\Widgets\Separator;
 
 class SeparatorTest extends TestCase
 {
diff --git a/tests/Widgets/SizegripTest.php b/tests/Widgets/SizegripTest.php
index 00465ca..a797f9f 100644
--- a/tests/Widgets/SizegripTest.php
+++ b/tests/Widgets/SizegripTest.php
@@ -1,9 +1,9 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Tests\Widgets;
+namespace Tkui\Tests\Widgets;
 
-use PhpGui\Tests\TestCase;
-use PhpGui\Widgets\Sizegrip;
+use Tkui\Tests\TestCase;
+use Tkui\Widgets\Sizegrip;
 
 class SizegripTest extends TestCase
 {
diff --git a/tests/Widgets/SpinboxTest.php b/tests/Widgets/SpinboxTest.php
index 4f29998..fdbf00b 100644
--- a/tests/Widgets/SpinboxTest.php
+++ b/tests/Widgets/SpinboxTest.php
@@ -1,9 +1,9 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Tests\Widgets;
+namespace Tkui\Tests\Widgets;
 
-use PhpGui\Tests\TestCase;
-use PhpGui\Widgets\Spinbox;
+use Tkui\Tests\TestCase;
+use Tkui\Widgets\Spinbox;
 
 class SpinboxTest extends TestCase
 {
diff --git a/tests/Widgets/TextEditStackTest.php b/tests/Widgets/TextEditStackTest.php
index b296768..8fb2270 100644
--- a/tests/Widgets/TextEditStackTest.php
+++ b/tests/Widgets/TextEditStackTest.php
@@ -1,10 +1,10 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Tests\Widgets;
+namespace Tkui\Tests\Widgets;
 
-use PhpGui\Tests\TestCase;
-use PhpGui\Widgets\Text\EditStack;
-use PhpGui\Widgets\Text\Text;
+use Tkui\Tests\TestCase;
+use Tkui\Widgets\Text\EditStack;
+use Tkui\Widgets\Text\Text;
 
 class TextEditStackTest extends TestCase
 {
diff --git a/tests/Widgets/TextTest.php b/tests/Widgets/TextTest.php
index e06cfe5..40ac936 100644
--- a/tests/Widgets/TextTest.php
+++ b/tests/Widgets/TextTest.php
@@ -1,12 +1,12 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Tests\Widgets;
+namespace Tkui\Tests\Widgets;
 
-use PhpGui\Image;
-use PhpGui\Tests\TestCase;
-use PhpGui\Widgets\Text\Range;
-use PhpGui\Widgets\Text\Text;
-use PhpGui\Widgets\Text\TextIndex;
+use Tkui\Image;
+use Tkui\Tests\TestCase;
+use Tkui\Widgets\Text\Range;
+use Tkui\Widgets\Text\Text;
+use Tkui\Widgets\Text\TextIndex;
 use PHPUnit\Framework\MockObject\MockObject;
 
 class TextTest extends TestCase
diff --git a/tests/Widgets/WindowTest.php b/tests/Widgets/WindowTest.php
index e285f0f..3dfc106 100644
--- a/tests/Widgets/WindowTest.php
+++ b/tests/Widgets/WindowTest.php
@@ -1,10 +1,10 @@
 <?php declare(strict_types=1);
 
-namespace PhpGui\Tests\Widgets;
+namespace Tkui\Tests\Widgets;
 
-use PhpGui\Tests\TestCase;
-use PhpGui\Windows\ChildWindow;
-use PhpGui\Windows\MainWindow;
+use Tkui\Tests\TestCase;
+use Tkui\Windows\ChildWindow;
+use Tkui\Windows\MainWindow;
 
 class WindowTest extends TestCase
 {