Partial Rendering Windows 7 Basic

Under Windows 7 basic mode(aero disabled), open a modal windows form on top of an openGL window. Close the modal form, only previously covered area by the modal form are redrawn and the remaining is unrefreshed.

It works fine when aero is on under Windows 7. Does anyone know why it happens and how to fix the problem?

This is normal behaviour with Windows GDI - only the area that needs refreshing gets refreshed. You’ll need to modify your rendering code to refresh the full window every time. Read up on the WM_PAINT message for more background info.

See here about mixing GDI and OpenGL on Vista/Windows 7: