Fix initial rectangle location.
 [rsc] --rw-rw-r-- M 15674 glenda sys 22791 Nov 10 10:21 sys/src/cmd/rio/rio.c
	/n/sourcesdump/2005/1110/plan9/sys/src/cmd/rio/rio.c:962,973 - 
	/n/sourcesdump/2005/1111/plan9/sys/src/cmd/rio/rio.c:962,974
	  	p = mouse->xy;
	  	
	  	which = whichcorner(w, p);
	- 	startp = cornerpt(w->screenr, p, which);
	- 	wmovemouse(w, startp);
	+ 	p = cornerpt(w->screenr, p, which);
	+ 	wmovemouse(w, p);
	  	readmouse(mousectl);
	  	r = whichrect(w->screenr, p, which);
	  	drawborder(r, 1);
	  	or = r;
	+ 	startp = p;
	  	but = mouse->buttons;
	  	while(mouse->buttons == but){
	  		p = onscreen(mouse->xy);