This function hangs with the following apps (at least) - Notepad Win 3.11 - Notepad NT 4 - Eudora 1.5
In all cases, the problem appears when a text has several pages and I try to scroll toward the beginning of text. The problem disappears if I comment out the calls to X11DRV_StartGraphicsExposure and X11DRV_EndGraphicsExposure. The apps seem to work just as well. The hanging occurs because there is no X event generated in X11DRV_EndGraphicsExposure. I don't quite see why there should be one in this case.
Gerard