### 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
case RenderingDevice::DeviceType::DEVICE_TYPE_VIRTUAL_GPU:
			device_type_string = "virtual";
			break;
		case RenderingDevice::DeviceType::DEVICE_TYPE_CPU:
			device_type_string = "(software emulation on CPU)";
			break;
		case RenderingDevice::DeviceType::DEVICE_TYPE_OTHER:
		case RenderingDevice::DeviceType::DEVICE_TYPE_MAX:
			break; 
	}
	const Vector<String> video_adapter_driver_info = OS::get_singleton()->get_video_adapter_driver_info();
	const String processor_name = OS::get_singleton()->get_processor_name();
	const int processor_count = OS::get_singleton()->get_processor_count();
	
	if (rendering_method == "forward_plus") {
		rendering_method = "Forward+";
	} else if (rendering_method == "mobile") {
		rendering_method = "Mobile";
	} else if (rendering_method == "gl_compatibility") {
		rendering_method = "Compatibility";
		driver_name = GLOBAL_GET("rendering/gl_compatibility/driver");
	}
	if (driver_name == "vulkan") {
		driver_name = "Vulkan";
	} else if (driver_name == "opengl3") {
		driver_name = "GLES3";
	}
	
	Vector<String> info;
	info.push_back(godot_version);