Apply #1252 and #1253 on V4:
Set slider arrow visibly on any change in gallery container dimenations.
When UNSAFE_componentWillReceiveProps in it's inner function we are calculating gallery position according to the old props (happens before props are changing).
Apply #1252 and #1253 on V4: Set slider arrow visibly on any change in gallery container dimenations. When UNSAFE_componentWillReceiveProps in it's inner function we are calculating gallery position according to the old props (happens before props are changing).