private void OnTabControlMouseMove(object sender, MouseEventArgs e) { if (e.Button != MouseButtons.Left) { return; } if (_movedPage != null && _point != Point.Empty && (Math.Abs(e.X - _point.X) > SystemInformation.DragSize.Width || (Math.Abs(e.Y - _point.Y) > SystemInformation.DragSize.Height))) { _tabControl.DoDragDrop(sender, DragDropEffects.Move); } }