### 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
for (int i = 0; i < plugins_list.size(); i++) {
		plugins_list[i]->make_visible(p_visible);
	}
}
void EditorPluginList::edit(Object *p_object) {
	for (int i = 0; i < plugins_list.size(); i++) {
		plugins_list[i]->edit(p_object);
	}
}
bool EditorPluginList::forward_gui_input(const Ref<InputEvent> &p_event) {
	bool discard = false;
	for (int i = 0; i < plugins_list.size(); i++) {
		if (plugins_list[i]->forward_canvas_gui_input(p_event)) {
			discard = true;
		}
	}
	return discard;
}
EditorPlugin::AfterGUIInput EditorPluginList::forward_3d_gui_input(Camera3D *p_camera, const Ref<InputEvent> &p_event, bool serve_when_force_input_enabled) {