### 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
project_run_bar->stop_playing();
	_save_all_scenes();
}
void EditorNode::save_scene_list(Vector<String> p_scene_filenames) {
	for (int i = 0; i < editor_data.get_edited_scene_count(); i++) {
		Node *scene = editor_data.get_edited_scene_root(i);
		if (scene && (p_scene_filenames.find(scene->get_scene_file_path()) >= 0)) {
			_save_scene(scene->get_scene_file_path(), i);
		}
	}
}
void EditorNode::save_before_run() {
	current_menu_option = FILE_SAVE_AND_RUN;
	_menu_option_confirm(FILE_SAVE_AS_SCENE, true);
	file->set_title(TTR("Save scene before running..."));
}
void EditorNode::try_autosave() {
	if (!bool(EDITOR_GET("run/auto_save/save_before_running"))) {
		return;
	}
	if (unsaved_cache) {
		Node *scene = editor_data.get_edited_scene_root();
		if (scene && !scene->get_scene_file_path().is_empty()) { 
			_save_scene_with_preview(scene->get_scene_file_path());
		}
	}
	_menu_option(FILE_SAVE_ALL_SCENES);
	editor_data.save_editor_external_data();
}
void EditorNode::restart_editor() {