MarkerConflict.xaml

<Canvas xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        x:Name="canvas">
  <Rectangle x:Name="Background"
             Opacity="0.8"
             Fill="Red"
             RadiusX="2"
             RadiusY="2" />
  <Rectangle x:Name="Border"
             Stroke="Black"
             RadiusX="2"
             RadiusY="2" />
  <Canvas.Resources>
    <Storyboard x:Name="Pulse">
      <DoubleAnimation From="0.0"
                       To="1.0"
                       Duration="00:00:00.3"
                       AutoReverse="true"
                       Storyboard.TargetName="canvas"
                       Storyboard.TargetProperty="(UIElement.Opacity)" />
    </Storyboard>
  </Canvas.Resources>
</Canvas>