I have an app with a list box with FluidBehavior applied to the items. Additionally, the items can be expanded or collapsed and they are animated between these states. The animation appeared choppy at times, so I applied CacheMode=BitmapCahce to a part of the item template .
That worked fine and I could see the caching taking place using WpfPerf. However , when the machines would go to sleep and wake up, the window that contains cached elements appeared hung with the WPF rendering thread consuming 40% CPU. The other funcionality ( other windows, self hosted WCF services ) still worked.