private static void OnTextChanged(DependencyObject o, DependencyPropertyChangedEventArgs e)
        {
            MultiLineTextEditor textEditor = o as MultiLineTextEditor;

            if (textEditor != null)
            {
                textEditor.OnTextChanged((string)e.OldValue, (string)e.NewValue);
            }
        }
        private static void OnIsOpenChanged(DependencyObject o, DependencyPropertyChangedEventArgs e)
        {
            MultiLineTextEditor multiLineTextEditor = o as MultiLineTextEditor;

            if (multiLineTextEditor != null)
            {
                multiLineTextEditor.OnIsOpenChanged((bool)e.OldValue, (bool)e.NewValue);
            }
        }