private void OnMouseUp(object sender, MouseButtonEventArgs e) { EndAction(); // Clear selection if this was a non-ctrl click outside of any item (i.e. in the background) Point currentPoint = e.GetPosition(content); double width = currentPoint.X - startPoint.X + 1; double height = currentPoint.Y - startPoint.Y + 1; if (Math.Abs(width) <= SystemParameters.MinimumHorizontalDragDistance && Math.Abs(height) <= SystemParameters.MinimumVerticalDragDistance && !SelectionMultiple.IsControlKeyDown) { treeView.ClearSelection(); } }