### 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
if (!get_window()->is_visible()) {
			return;
		}
		Window *grandparent_window = get_window()->get_parent_visible_window();
		ERR_FAIL_COND(!grandparent_window);
		if (Object::cast_to<InputEventKey>(p_event.ptr()) || Object::cast_to<InputEventShortcut>(p_event.ptr())) {
			
			grandparent_window->push_input(p_event);
			if (grandparent_window->is_input_handled()) {
				get_viewport()->set_input_as_handled();
			}
		}
	}
};
Rect2 WindowWrapper::_get_default_window_rect() const {
	
	return wrapped_control->get_screen_rect();
}
Node *WindowWrapper::_get_wrapped_control_parent() const {
	if (margins) {
		return margins;
	}
	return window;
}
void WindowWrapper::_set_window_enabled_with_rect(bool p_visible, const Rect2 p_rect) {