+ else if (event->xany.type == ButtonPress &&
+ (event->xbutton.button == Button4 ||
+ event->xbutton.button == Button5 ||
+ event->xbutton.button == Button6 ||
+ event->xbutton.button == Button7))
+ {
+ gltrackball_mousewheel (gp->trackball, event->xbutton.button, 10,
+ !!event->xbutton.state);
+ return True;
+ }