### 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
HashMap<StringName, Variant> modified_properties = get_modified_properties_for_node(p_node);
		
		List<Connection> connections_to;
		p_node->get_all_signal_connections(&connections_to);
		List<ConnectionWithNodePath> valid_connections_to;
		for (const Connection &c : connections_to) {
			Node *connection_target_node = Object::cast_to<Node>(c.callable.get_object());
			if (connection_target_node) {
				
				if (!c.callable.is_custom()) {
					ConnectionWithNodePath connection_to;
					connection_to.connection = c;
					connection_to.node_path = p_node->get_path_to(connection_target_node);
					valid_connections_to.push_back(connection_to);
				}
			}
		}
		
		List<Connection> connections_from;
		p_node->get_signals_connected_to_this(&connections_from);
		List<Connection> valid_connections_from;
		for (const Connection &c : connections_from) {
			Node *source_node = Object::cast_to<Node>(c.signal.get_object());
			Node *valid_source_owner = nullptr;
			if (source_node) {
				valid_source_owner = source_node->get_owner();
				while (valid_source_owner) {
					if (valid_source_owner == p_root) {
						break;
					}