The first time I call wglUseFontBitmaps everything works fine but it fails on subsequent calls with error code 87, which I think indicates invalid parameter. Before calling it the second time I have deleted the display lists and use exactly the same parameters. Can anyone take a guess about what I’m doing wrong? I originally encountered the problem when switching gl context for full screen display, after which I need to rebuild display lists, hence the need to call wglUseFontBitmaps again. But the error is the same even if the gl context is not changed.