Issue Description:

I have a UICollectionView and i have added a KVO on UICollectionViewCell item

internal class DayCollectionCell: UICollectionViewCell {

... some code
 
observation = self.observe(\DayCollectionCell.isSelected, options: [.initial, .new, .old], changeHandler: selectionDidChange)

... some code

}

based on certain conditional validation, i'm returning false from the shouldSelectItem delegate method on UICollectionView. This delegate method is called when i select an item on the UICollectionView.

Also, strangely, this method is called after the observer is called. I would expect observer on isSelected to be called based on my boolean value in shouldSelectItem - as this event will actually advise whether the item should be selected or not.

Actual Result:

Irrespective of whether i return true / false, the observer is always called.

Expected Result:

It should fire the observer only if i return true from shouldSelectItem.