
Instead of setting the x/y position of the box pointer, which results in a long change of workarounds for limitations of the Clutter layout system, set the anchor point instead, which takes the positioning out of the layout system. The position is computed as a combination of the position computed from the allocation and the box pointer's size, and an offset that we tween when animating showing and hiding the box pointer. https://bugzilla.gnome.org/show_bug.cgi?id=645744