### 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
return wrapped_control;
}
Control *WindowWrapper::release_wrapped_control() {
	set_window_enabled(false);
	if (wrapped_control) {
		Control *old_wrapped = wrapped_control;
		wrapped_control->get_parent()->remove_child(wrapped_control);
		wrapped_control = nullptr;
		return old_wrapped;
	}
	return nullptr;
}
bool WindowWrapper::is_window_available() const {
	return window != nullptr;
}
bool WindowWrapper::get_window_enabled() const {
	return is_window_available() ? window->is_visible() : false;
}
void WindowWrapper::set_window_enabled(bool p_enabled) {
	_set_window_enabled_with_rect(p_enabled, _get_default_window_rect());
}
Rect2i WindowWrapper::get_window_rect() const {
	ERR_FAIL_COND_V(!get_window_enabled(), Rect2i());
	return Rect2i(window->get_position(), window->get_size());
}
int WindowWrapper::get_window_screen() const {
	ERR_FAIL_COND_V(!get_window_enabled(), -1);
	return window->get_current_screen();
}
void WindowWrapper::restore_window(const Rect2i &p_rect, int p_screen) {