rio: cancel window selection if pointer ends outside window
 [rsc] --rw-rw-r-- M 521269 glenda sys 22866 Mar 13 17:30 sys/src/cmd/rio/rio.c
	/n/sourcesdump/2006/0313/plan9/sys/src/cmd/rio/rio.c:1011,1017 - 
	/n/sourcesdump/2006/0314/plan9/sys/src/cmd/rio/rio.c:1011,1017
	  		w = wpointto(mouse->xy);
	  	else
	  		w = nil;
	- 	if(wait)
	+ 	if(wait){
	  		while(mouse->buttons){
	  			if(mouse->buttons!=4 && w !=nil){	/* cancel */
	  				cornercursor(input, mouse->xy, 0);
	/n/sourcesdump/2006/0313/plan9/sys/src/cmd/rio/rio.c:1019,1024 - 
	/n/sourcesdump/2006/0314/plan9/sys/src/cmd/rio/rio.c:1019,1027
	  			}
	  			readmouse(mousectl);
	  		}
	+ 		if(w != nil && wpointto(mouse->xy) != w)
	+ 			w = nil;
	+ 	}
	  	cornercursor(input, mouse->xy, 0);
	  	moveto(mousectl, mouse->xy);	/* force cursor update; ugly */
	  	menuing = FALSE;