diff --git a/traitsui/examples/demo/Advanced/List_editors_demo.py b/traitsui/examples/demo/Advanced/List_editors_demo.py
index 237439dd8..840ec47b9 100644
--- a/traitsui/examples/demo/Advanced/List_editors_demo.py
+++ b/traitsui/examples/demo/Advanced/List_editors_demo.py
@@ -129,7 +129,7 @@ class ListTraitTest(HasStrictTraits):
     with tester.create_ui(demo) as ui:
         main_tab = tester.find_by_id(ui, "splitter")
         main_tab.locate(locator.Index(1)).perform(command.MouseClick())
-        list_ = tester.find_by_id(ui, "list").locate(locator.Index(1))
+        list_ = tester.find_by_id(ui, "list").locate(locator.Index(3))
         list_.find_by_name("name").perform(command.KeySequence("\b\b\b\bDavid"))
 
         main_tab.locate(locator.Index(2)).perform(command.MouseClick())
diff --git a/traitsui/testing/qt4/default_registry.py b/traitsui/testing/qt4/default_registry.py
index beca22d28..97a67e492 100644
--- a/traitsui/testing/qt4/default_registry.py
+++ b/traitsui/testing/qt4/default_registry.py
@@ -118,8 +118,9 @@ def mouse_click_index_with_layout(interactor, action):
 
 def nested_ui_index_with_custom_list_editor(interactor, action):
     index = interactor.location.index
+    row, column = divmod(index, interactor.editor.factory.columns)
     grid_layout = interactor.editor._list_pane.layout()
-    widget = grid_layout.itemAt(index).widget()
+    widget = grid_layout.itemAtPosition(row, column).widget()
     return widget._editor._ui