Signum.Windows.AutocompleteTextBox.userControl_PreviewMouseDown C# (CSharp) Метод

        private void userControl_PreviewMouseDown(object sender, MouseButtonEventArgs e)
        {
            //Console.WriteLine("Down");
            if (!txtBox.IsMouseOver && !pop.IsMouseOver)
            {
                ReleaseMouseCapture();
                Close(CloseReason.ClickOut);
            }
            else if (pop.IsMouseOver)
            {
                var sb = lstBox.Child<ScrollBar>(WhereFlags.VisualTree);
                if (!sb.IsMouseOver)
                {
                    ReleaseMouseCapture();
                    Commit(CloseReason.ClickList);
                }
            }

        }