Arranged subviews getting permanantly stuck in temporary state

[art42]

Placing fingers in multiple UIViews simultaneously causes the one of the views to get stuck in the 'temporary state' permanently - the original view never becomes unhidden (alpha not restored to 1) and the temporary view does not go away. It happened twice in the photo below.

[origami-z]

I believe multiple selection is not the intention here?

Maybe just add a check of existence before addLongPressGestureRecognizerForReorderingToView