### 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
List<Ref<Resource>> changed;
	int rc = p_resources.size();
	for (int i = 0; i < rc; i++) {
		Ref<Resource> res = ResourceCache::get_ref(p_resources.get(i));
		if (res.is_null()) {
			continue;
		}
		if (!res->editor_can_reload_from_file()) {
			continue;
		}
		if (!res->get_path().is_resource_file() && !res->get_path().is_absolute_path()) {
			continue;
		}
		if (!FileAccess::exists(res->get_path())) {
			continue;
		}
		if (!res->get_import_path().is_empty()) {
			
			continue;
		}
		changed.push_back(res);
	}
	if (changed.size()) {
		for (Ref<Resource> &res : changed) {
			res->reload_from_file();
		}
	}
}
void EditorNode::_fs_changed() {