private void lb_ShowText_MouseMove(object sender, MouseEventArgs e) { if (ModifierKeys == Keys.Control && MouseButtons == MouseButtons.Left && this.Location != PaintManager.CurrentView.PointToClient(MousePosition.AddOffset(new Point(-MouseDownPosition.X, -MouseDownPosition.Y)))) { this.Location = PaintManager.CurrentView.PointToClient(MousePosition.AddOffset(new Point(-MouseDownPosition.X, -MouseDownPosition.Y))); } }