### 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
if (bool(EDITOR_GET("run/output/always_clear_output_on_play"))) {
		log->clear();
	}
	if (bool(EDITOR_GET("run/output/always_open_output_on_play"))) {
		make_bottom_panel_item_visible(log);
	}
}
void EditorNode::_project_run_stopped() {
	if (!bool(EDITOR_GET("run/output/always_close_output_on_stop"))) {
		return;
	}
	for (int i = 0; i < bottom_panel_items.size(); i++) {
		if (bottom_panel_items[i].control == log) {
			_bottom_panel_switch(false, i);
			break;
		}
	}
}
void EditorNode::notify_all_debug_sessions_exited() {
	project_run_bar->stop_playing();
}
void EditorNode::add_io_error(const String &p_error) {
	DEV_ASSERT(Thread::get_caller_id() == Thread::get_main_id());
	singleton->load_errors->add_image(singleton->gui_base->get_theme_icon(SNAME("Error"), SNAME("EditorIcons")));
	singleton->load_errors->add_text(p_error + "\n");
	EditorInterface::get_singleton()->popup_dialog_centered_ratio(singleton->load_error_dialog, 0.5);
}
void EditorNode::add_io_warning(const String &p_warning) {