### Godot version

v4.2.dev.custom_build [0c2144da9]

### System information

Debian Linux X11 Xfce

### Issue description

Prerequisite: Be in Single Window Mode in the Editor
The Filesystem Dock is unusable when it is floating, which is not expected.
It appears garbled in the top-left corner:
![image](https://github.com/godotengine/godot/assets/6299227/109f7922-97de-44c3-814a-ca7f970e0602)

The following errors are shown:
```
  editor/window_wrapper.cpp:220 - Condition "!is_window_available()" is true.
  editor/window_wrapper.cpp:202 - Condition "!get_window_enabled()" is true. Returning: Rect2i()
  editor/window_wrapper.cpp:207 - Condition "!get_window_enabled()" is true. Returning: -1
  editor/window_wrapper.cpp:207 - Condition "!get_window_enabled()" is true. Returning: -1
```

bisecting lead to #62378
possibly related to #44439

### Steps to reproduce

1. Start a project in the Editor
2. Switch to Single Window Mode in the Editor and reload (if necessary)
3. Make the Filesystem Dock floating

### Minimal reproduction project

Editor issue
break;
						case EditorUndoRedoManager::REMOTE_HISTORY:
							log->add_message(vformat(TTR("Remote Undo: %s"), action), EditorLog::MSG_TYPE_EDITOR);
							break;
						default:
							log->add_message(vformat(TTR("Scene Undo: %s"), action), EditorLog::MSG_TYPE_EDITOR);
					}
				}
			}
		} break;
		case EDIT_REDO: {
			EditorUndoRedoManager *undo_redo = EditorUndoRedoManager::get_singleton();
			if ((int)Input::get_singleton()->get_mouse_button_mask() & 0x7) {
				log->add_message(TTR("Can't redo while mouse buttons are pressed."), EditorLog::MSG_TYPE_EDITOR);
			} else {
				if (!undo_redo->redo()) {
					log->add_message(TTR("Nothing to redo."), EditorLog::MSG_TYPE_EDITOR);
				} else {
					String action = undo_redo->get_current_action_name();
					if (action.is_empty()) {
						break;
					}
					switch (undo_redo->get_current_action_history_id()) {
						case EditorUndoRedoManager::GLOBAL_HISTORY:
							log->add_message(vformat(TTR("Global Redo: %s"), action), EditorLog::MSG_TYPE_EDITOR);
							break;
						case EditorUndoRedoManager::REMOTE_HISTORY:
							log->add_message(vformat(TTR("Remote Redo: %s"), action), EditorLog::MSG_TYPE_EDITOR);
							break;
						default: