For example something like the following, often happens in environments with using Remote Desktop connections:
In such cases you can change the used video renderer for the VideoEWO, by creating a textfile with the name "AccVimaccGui.conf" in "<WinCC_OA_Proj>/data/VideoOA", with the following content:
    [General]
    ; Use one of opengl | ddraw | software | ddraw_auto (default is opengl).
    ; With VideoRenderer=opengl the GLRenderer will be used.
    ; ddraw_auto will automatically choose between ddraw and software.
    ;
    ; If you do not have any video hardware accellaration at all you can go with:
    ; VideoRenderer=software
    VideoRenderer=opengl
While setting the VideoRenderer to "ddraw", "software" or "ddraw_auto" you changes the renderer to something else like the default.
Where "software" is of cause the option which always works as a fallback, this is always the option with the lowest possible performance, cause it's disables any GPU support.
IMPORTANT: Any changes to this settings will only getting active, after closing any running WinCC OA UI and restart them.
Example after changing setting from "opengl" to "ddraw_auto" on a machine with NVIDIA GPU, used in a RDP connection: