O'Reilly Media, Inc. 4/5/2012 Figure 4-8. Three distortion effects applied to checkerboard. Distortion effects require extra work if you want them to behave in a predictable fashion. When you apply a distortion effect to an interactive element like a list box (Figure 4- 9(a)), the touch, stylus and mouse events won't work as expected. The pixel shader is rearranging the output pixels but the Silverlight/WPF hit-testing infrastructure is unaware that the pixels are in a new location (Figure 4-9(b)). 23