on os x (10.39), and using pd 0.39.2 extended test 7, i'm getting this weird behaviour with the gui redraw.
using a 20x20 pixel canvas as a cursor, and sending a [pos xy< message to change the cursor's position, the gui redraw is really blocky.
BUT, if i hold down a key on the keyboard (any key seems to work), the gui redraws suddenly work really smoothly, and the 20x20 pixel canvas glides across the screen beautifully.
the same thing happens with other gui objects (number boxes etc) too.
attached is a patch that demonstates this.
basically, the nice smooth action when i hold down a key is what i am after, but i don't want to have to hold down a key to do that.