Old hardware accelearation method. http://msdn.microsoft.com/en-us/library/windows/desktop/dd390946.aspx http://msdn.microsoft.com/en-us/library/windows/deskto

Old hardware accelearation method. http://msdn.microsoft.com/en-us/library/windows/desktop/dd390946.aspx http://msdn.microsoft.com/en-us/library/windows/desktop/dd39... Since Vista it's disabled by default and incompatible with DWM.