add: XDrawLine(dpy, w, gc, cx+20, 0, cx+20, h);
context: static void splitterHandler(XEvent *event, void *data){    WMTableView *table = (WMTableView*)data;    int done = 0;        while (!done) {	XEvent ev;		WMMaskEvent(event->xany.display, ButtonMotionMask|ButtonReleaseMask,		    &ev);		switch (event->type) {	 case MotionNotify:	    printf("%i\n", event->xmotion.x);	    break;	    	 case ButtonRelease:	    done = 1;	    break;	}    }}