### 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
p_ownership_table.insert(p_current_node, p_current_node->get_owner());
	for (int i = 0; i < p_current_node->get_child_count(); i++) {
		Node *child = p_current_node->get_child(i);
		update_ownership_table_for_addition_node_ancestors(child, p_ownership_table);
	}
}
void EditorNode::update_diff_data_for_node(
		Node *p_edited_scene,
		Node *p_root,
		Node *p_node,
		HashMap<NodePath, ModificationNodeEntry> &p_modification_table,
		List<AdditiveNodeEntry> &p_addition_list) {
	bool node_part_of_subscene = p_node != p_edited_scene &&
			p_edited_scene->get_scene_inherited_state().is_valid() &&
			p_edited_scene->get_scene_inherited_state()->find_node_by_path(p_edited_scene->get_path_to(p_node)) >= 0;
	
	Node *valid_node_owner = p_node->get_owner();
	while (valid_node_owner) {
		if (valid_node_owner == p_root) {
			break;
		}
		valid_node_owner = valid_node_owner->get_owner();
	}
	if ((valid_node_owner == p_root && (p_root != p_edited_scene || !p_edited_scene->get_scene_file_path().is_empty())) || node_part_of_subscene || p_node == p_root) {