### 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
Array rc = EditorSettings::get_singleton()->get_project_metadata("recent_files", "scenes", Array());
	recent_scenes->clear();
	String path;
	for (int i = 0; i < rc.size(); i++) {
		path = rc[i];
		recent_scenes->add_item(path.replace("res:", ""), i);
	}
	recent_scenes->add_separator();
	recent_scenes->add_shortcut(ED_SHORTCUT("editor/clear_recent", TTR("Clear Recent Scenes")));
	recent_scenes->reset_size();
}
void EditorNode::_quick_opened() {
	Vector<String> files = quick_open->get_selected_files();
	bool open_scene_dialog = quick_open->get_base_type() == "PackedScene";
	for (int i = 0; i < files.size(); i++) {
		String res_path = files[i];
		List<String> scene_extensions;
		ResourceLoader::get_recognized_extensions_for_type("PackedScene", &scene_extensions);
		if (open_scene_dialog || scene_extensions.find(files[i].get_extension().to_lower())) {
			open_request(res_path);
		} else {
			load_resource(res_path);
		}
	}
}
void EditorNode::_project_run_started() {