Thanks guys, I did some more testing together with a developer, it seems like that the issue occurs whenever a program renders its OpenGL content into a 'child window' instead of directly into a top level window. The qtgears.exe uses child windows, other simple test applications e. g. from the DirectX9 SDK without rendering to child windows seem to work ok or had other failures. He said that "it's that 'render to child window' code path in Wine that seems to not function properly on OSX - it seems to need some particular kind of OpenGL extension that Apple does not happen to implement." Thus a downgrade to XQuartz 2.6.3 did not resolve this issue either. I was not aware that Wine's primary concern is working with Linux, I know this is already a big task, and obviously there are some differences to the Mac OS X flavor of Unix... Thanks again for your support, Chyman
