static void onContentWidthChangedCallback(DependencyObject dobj, DependencyPropertyChangedEventArgs args)
        {
            CustomChildWindow control = dobj as CustomChildWindow;

            if (control != null)
            {
                if (control.contentControl != null && !double.IsNaN(control.ContentWidth))
                {
                    control.contentControl.Width = control.ContentWidth;
                }
            }
        }
        static void onShowTitelBorderChangedCallback(DependencyObject dobj, DependencyPropertyChangedEventArgs args)
        {
            CustomChildWindow control = dobj as CustomChildWindow;

            if (control != null)
            {
                if (control.titelBorder != null)
                {
                    control.titelBorder.Visibility = control.ShowTitelBorder;
                }
            }
        }