Open Radar

 
Summary:
When a collection view animation pushes a UICollectionElementKindSectionHeader off of the screen (thus removing it from the cell pool) its last known origin point is lost. A demo for this bug and my workaround can be found here: https://github.com/adamyanalunas/CollectionViewHeaderPlacement/

Steps to Reproduce:
1. In a collection view that has properly showing headers, cells, and supplementary views increase the size of a supplementary view—via performBatchUpdates animation—to an extent that a header is pushed off screen
2. Reverse the supplementary view resizing so the header can return to screen

Expected Results:
Header animates in from last known origin, giving the user the feeling that the screen space is infinite and they have but a partial view

Actual Results:
When the collection view animates again in a manner that would allow the header to return to screen it animates in from {0,0} instead of the last known origin, surprising the user and making for a lame experience.

Regression:
Unknown how far back this bug reaches.

Notes:
A demo for this bug and my workaround can be found here: https://github.com/adamyanalunas/CollectionViewHeaderPlacement/