appDisplay: Animate opening app icons menu
Fixes #2335 (closed)
But I'm not sure if I should do more digging and try to find out if it's due to something changing with PopupMenu / BoxPointer and if we need to change it there. (But that would also be a bit more dangerous)
I'm also not sure why it's not needed for the close animation. Well the
animation is rather quick, not even to sure it's animating on close.