简要的分析完各种窗口的结构之后，我们要回到窗口中重要的一个部分——window和slot；在window的结构中我们并没有直接看到slot，它有一层中间层window pane，我们先看一下这个pane在src/peony-window-pane.h中：
/* A PeonyWindowPane is a layer between a slot and a window.
* Each slot is contained in one pane, and each pane can contain
* one or more slots. It also supports the notion of an "active slot".
* On the other hand, each pane is contained in a window, while each
* window can contain one or multiple panes. Likewise, the window has
* the notion of an "active pane".
*
* A spatial window has only one pane, which contains a single slot.
* A navigation window may have one or more panes.
*/
struct _PeonyWindowPane
{
GObject parent;
/* hosting window */
PeonyWindow *window;
gboolean visible;
/* available slots, and active slot.
* Both of them may never be NULL. */
GList *slots;
GList *active_slots;
PeonyWindowSlot *active_slot;
/* whether or not this pane is active */
gboolean is_active;
};继续看这个slot类，在src/peony-window-slot.h中
/* Each PeonyWindowSlot corresponds to
* a location in the window for displaying
* a PeonyView.
*
* For navigation windows, this would be a
* tab, while spatial windows only have one slot.
*/
struct PeonyWindowSlot
{
GObject parent;
PeonyWindowPane *pane;
/* content_box contains
* 1) an event box containing extra_location_widgets
* 2) the view box for the content view
*/
GtkWidget *content_box;
GtkWidget *extra_location_frame;
GtkWidget *extra_location_widgets;
GtkWidget *view_box;
PeonyView *content_view;
PeonyView *new_content_view;
/* Information about bookmarks */
PeonyBookmark *current_location_bookmark;
PeonyBookmark *last_location_bookmark;
/* Current location. */
GFile *location;
char *title;
char *status_text;
PeonyFile *viewed_file;
gboolean viewed_file_seen;
gboolean viewed_file_in_trash;
gboolean allow_stop;
PeonyQueryEditor *query_editor;
/* New location. */
PeonyLocationChangeType location_change_type;
guint location_change_distance;
GFile *pending_location;
char *pending_scroll_to;
GList *pending_selection;
PeonyFile *determine_view_file;
GCancellable *mount_cancellable;
GError *mount_error;
gboolean tried_mount;
PeonyWindowGoToCallback open_callback;
gpointer open_callback_user_data;
GCancellable *find_mount_cancellable;
gboolean visible;
};我们又看到了文件管理器中一个关键类PeonyView，它实际上是之前我们提及过的content view；可以看出实际上上图中的content view并不是直接在window中的，而是由slot进行管理，我们最后会将content view填入window的content box中，这个box实际上是slot的cotent box。
我们整理一下window-pane-slot的关系
| window | pane/active-pane | slot/active-pane | pane/active-slot-in-pane |
|---|---|---|---|
| spatial window | 1/1 | 1/1 | 1/1 |
| peony-navigation-window | 1/1 | n/1 | 1/1 |
| caja-navigation-window | 2/1 | n/1 | 1/1 |
由于spatial window之所以简单，只有一个slot也是重要的原因之一，而对于navigation window来说，是可以有多个pane和slot的，这个关系图可以用一张caja的截图表示的很清楚
在peony中，由于我们对工具栏和location bar的修改破坏了原有caja的架构，所以extra view就被禁用了。事实上这个pane的架构在我看来也不是很实用，我们下面着重分析一下这个slot究竟是如何运作的。