private void RegionClickCanvas_MouseDown(object sender, MouseButtonEventArgs e) { if (e.RightButton == MouseButtonState.Pressed) { return; } isSelecting = true; RegionClickCanvas.CaptureMouse(); CursorClipper.ClipCursor(this); clickedPoint = e.GetPosition(this); selectBorder.Height = 1; selectBorder.Width = 1; try { RegionClickCanvas.Children.Remove(selectBorder); } catch (Exception) { } selectBorder.BorderThickness = new Thickness(2); System.Windows.Media.Color borderColor = System.Windows.Media.Color.FromArgb(255, 40, 118, 126); selectBorder.BorderBrush = new SolidColorBrush(borderColor); _ = RegionClickCanvas.Children.Add(selectBorder); Canvas.SetLeft(selectBorder, clickedPoint.X); Canvas.SetTop(selectBorder, clickedPoint.Y); }