Following-up: it may not have actually been the ActiPro controls that caused an issue but something seriously hinky is going on. Please feel free to change this from bug to question, but the basic issue is that all of our animations are wrapped in VisualBrush styles so they can be simply dropped into anywhere you can apply a brush like foreground, background and fill attributes. That also makes it super convenient to setup converters to choose the appropriate brush based on a piece of data in a binding. For some reason the Loaded events, which trigger the storyboards to animate, are never getting called anymore. I figured it may be due to virtualization but I made a test project with the same basic RibbonWindow and Docking controls we're using in our main project and copied the ResourceDictionary with our animations and brushes verbatim and they work in the test project. Since they work fine in the test project but not in the larger project - any idea why the Loaded events in our VisualBrush animations may not be firing and kicking off their storyboards in one but not the other?