Cancel line on right click

samples/ReactiveHistorySample.Avalonia/App.xaml.cs

@@ -91,6 +91,15 @@ namespace ReactiveHistorySample.Avalonia
                             layerCanvas.InvalidateVisual();
                         }
                     }
+                    else if (args.MouseButton == MouseButton.Right)
+                    {
+                        if (line != null)
+                        {
+                            layer1.Shapes.Remove(line);
+                            line = null;
+                            layerCanvas.InvalidateVisual();
+                        }
+                    }
                 };
 
                 layerCanvas.PointerMoved += (sender, args) =>

samples/ReactiveHistorySample.Wpf/App.xaml.cs

@@ -69,6 +69,16 @@ namespace ReactiveHistorySample.Wpf
                     }
                 };
 
+                layerCanvas.PreviewMouseRightButtonDown += (sender, args) =>
+                {
+                    if (line != null)
+                    {
+                        layer1.Shapes.Remove(line);
+                        line = null;
+                        layerCanvas.InvalidateVisual();
+                    }
+                };
+
                 layerCanvas.PreviewMouseMove += (sender, args) =>
                 {
                     var point = args.GetPosition(layerCanvas);