### 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
_menu_option_confirm(p_option, false);
}
void EditorNode::_menu_confirm_current() {
	_menu_option_confirm(current_menu_option, true);
}
void EditorNode::_dialog_display_save_error(String p_file, Error p_error) {
	if (p_error) {
		switch (p_error) {
			case ERR_FILE_CANT_WRITE: {
				show_accept(TTR("Can't open file for writing:") + " " + p_file.get_extension(), TTR("OK"));
			} break;
			case ERR_FILE_UNRECOGNIZED: {
				show_accept(TTR("Requested file format unknown:") + " " + p_file.get_extension(), TTR("OK"));
			} break;
			default: {
				show_accept(TTR("Error while saving."), TTR("OK"));
			} break;
		}
	}
}
void EditorNode::_dialog_display_load_error(String p_file, Error p_error) {