Assume that you run an application that has a topmost window on a computer that is running Windows 7 or Windows Server 2008 R2. When you click the Show Desktop button two times, or when you press the Windows logo key+D two times, a non-topmost window appears above the topmost window. Additionally, the non-topmost window is formatted with the topmost property unexpectedly.

If you are facing this problem, apply this hotfix from KB2743148.