fix monitor select when no focus

dmenu.c

@@ -509,7 +509,7 @@ setup(void) {
 		XWindowAttributes wa;
 
 		XGetInputFocus(dc->dpy, &w, &di);
-		if(w != root && XGetWindowAttributes(dc->dpy, w, &wa))
+		if(w != root && w != PointerRoot && w != None && XGetWindowAttributes(dc->dpy, w, &wa))
 			XTranslateCoordinates(dc->dpy, root, root, wa.x, wa.y, &x, &y, &dw);
 		else
 			XQueryPointer(dc->dpy, root, &dw, &dw, &x, &y, &di, &di, &du);