### 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
tab_preview_panel->hide();
	if (p_tab == editor_data.get_edited_scene()) {
		return; 
	}
	set_current_scene(p_tab);
}
Button *EditorNode::add_bottom_panel_item(String p_text, Control *p_item) {
	Button *tb = memnew(Button);
	tb->set_flat(true);
	tb->connect("toggled", callable_mp(this, &EditorNode::_bottom_panel_switch).bind(bottom_panel_items.size()));
	tb->set_text(p_text);
	tb->set_toggle_mode(true);
	tb->set_focus_mode(Control::FOCUS_NONE);
	bottom_panel_vb->add_child(p_item);
	bottom_panel_hb->move_to_front();
	bottom_panel_hb_editors->add_child(tb);
	p_item->set_v_size_flags(Control::SIZE_EXPAND_FILL);
	p_item->hide();
	BottomPanelItem bpi;
	bpi.button = tb;
	bpi.control = p_item;
	bpi.name = p_text;
	bottom_panel_items.push_back(bpi);
	return tb;
}
void EditorNode::hide_bottom_panel() {