add: ev.xselection.selection = event->xselectionrequest.selection;
context: notifySelection(XEvent *event, Atom prop){    XEvent ev;/*    printf("envent to %x\n", event->xselectionrequest.requestor);*/    ev.xselection.type = SelectionNotify;    ev.xselection.serial = 0;    ev.xselection.send_event = True;    ev.xselection.display = event->xselectionrequest.display;    ev.xselection.requestor = event->xselectionrequest.requestor;    ev.xselection.target = event->xselectionrequest.target;    ev.xselection.property = prop;    ev.xselection.time = event->xselectionrequest.time;        XSendEvent(event->xany.display, event->xselectionrequest.requestor, 	       False, 0, &ev);    XFlush(event->xany.display);}