private void OnUnloaded(object sender, RoutedEventArgs e) {
if (!_loaded) return;
_loaded = false;
FancyBackgroundManager.Instance.RemoveListener(this);
AboutHelper.Instance.PropertyChanged -= About_PropertyChanged;
if (_hook == null) return;
try {
HwndSource.FromHwnd(new WindowInteropHelper(this).Handle)?.RemoveHook(_hook);
} catch (Exception) {
Logging.Warning("Can’t remove one-instance hook");
}
_hook = null;
}