A window that has the WS_EX_TOPMOST extended window style removed is displayed above other windows

Consider the following scenario:
  • You run an application that creates a topmost window by using the WS_EX_TOPMOST extended window style on a computer that is running Windows 8.1 or Windows Server 2012 R2.
  • The application calls the SetWindowPos function together with an hwndInsertAfter parameter whose value is set to HWND_NOTOPMOST in order to remove the WS_EX_TOPMOST extended window style from the window.

In this scenario, the window that no longer has the WS_EX_TOPMOST extended window style may be displayed incorrectly above other windows that have the WS_EX_TOPMOST extended window style.

Update information

The fix for this problem is included in security update 3002885. This update is dated November 11, 2014.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
Learn about the terminology that Microsoft uses to describe software updates.

Article ID: 3008241 - Last Review: 06/17/2015 19:44:00 - Revision: 2.0

Windows Server 2012 R2 Datacenter, Windows Server 2012 R2 Essentials, Windows Server 2012 R2 Foundation, Windows Server 2012 R2 Standard, Windows 8.1, Windows 8.1 Enterprise, Windows 8.1 Pro

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