### 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
int new_index = editor_data.get_edited_scene();
	int old_index = new_index;
	if (new_index > 0) {
		new_index = new_index - 1;
	} else if (editor_data.get_edited_scene_count() > 1) {
		new_index = 1;
	} else {
		editor_data.add_edited_scene(-1);
		new_index = 1;
	}
	if (p_change_tab) {
		_scene_tab_changed(new_index);
	}
	editor_data.remove_scene(old_index);
	_update_title();
	_update_scene_tabs();
}
void EditorNode::_remove_scene(int index, bool p_change_tab) {
	
	
	editor_data.clear_script_icon_cache();
	if (editor_data.get_edited_scene() == index) {
		
		_remove_edited_scene(p_change_tab);
	} else {
		
		editor_data.remove_scene(index);
	}
}
void EditorNode::set_edited_scene(Node *p_scene) {