### 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
Node *scene = editor_data.get_edited_scene_root(p_idx);
	if (!scene) {
		return;
	}
	String path = EditorPaths::get_singleton()->get_project_settings_dir().path_join(p_file.get_file() + "-editstate-" + p_file.md5_text() + ".cfg");
	Ref<ConfigFile> cf;
	cf.instantiate();
	Dictionary md;
	if (p_idx < 0 || editor_data.get_edited_scene() == p_idx) {
		md = editor_data.get_editor_plugin_states();
	} else {
		md = editor_data.get_scene_editor_states(p_idx);
	}
	List<Variant> keys;
	md.get_key_list(&keys);
	for (const Variant &E : keys) {
		cf->set_value("editor_states", E, md[E]);
	}
	
	List<Node *> selection = editor_selection->get_full_selected_node_list();
	TypedArray<NodePath> selection_paths;
	for (Node *selected_node : selection) {
		selection_paths.push_back(selected_node->get_path());
	}
	cf->set_value("editor_states", "selected_nodes", selection_paths);
	Error err = cf->save(path);
	ERR_FAIL_COND_MSG(err != OK, "Cannot save config file to '" + path + "'.");
}
bool EditorNode::_find_and_save_resource(Ref<Resource> p_res, HashMap<Ref<Resource>, bool> &processed, int32_t flags) {