Try to avoid nibbling on window borders.
 [rsc] --rw-rw-r-- M 12721 glenda sys 3366 Dec 31 16:07 sys/src/libframe/frdraw.c
	/n/sourcesdump/2005/1231/plan9/sys/src/libframe/frdraw.c:125,130 - 
	/n/sourcesdump/2006/0101/plan9/sys/src/libframe/frdraw.c:125,133
	  		return;
	  	pt.x--;	/* looks best just left of where requested */
	  	r = Rect(pt.x, pt.y, pt.x+FRTICKW, pt.y+f->font->height);
	+ 	/* can go into left border but not right */
	+ 	if(r.max.x > f->r.max.x)
	+ 		r.max.x = f->r.max.x;
	  	if(ticked){
	  		draw(f->tickback, f->tickback->r, f->b, nil, pt);
	  		draw(f->b, r, f->tick, nil, ZP);
 [rsc] --rw-rw-r-- M 12721 glenda sys 3366 Dec 31 16:07 sys/src/libframe/frdraw.c