In our application, when we are running in Windows High Contrast mode, our open, but hidden tool windows are rendered correctly. But when we tell the OS to switch back to normal mode, everything in our application switches back correctly, except those hidden tool windows. The Hidden tool windows are stuck in high contrast mode. All other tool windows are working just fine. It's only those tool windows that are unpinned (e.g. hidden). I ran the ActiPro Docking sample application, and everything behaves correctly there... so there's obviously a bug in our application. But I wanted to ask for any advice on how to hunt down this problem. Oh, and btw, the problem occurs exactly the same on XP and Windows 7. Thanks.