Crash with nil header

[oks]

In your method:

- (UICollectionReusableView *)collectionView:(UICollectionView *)collectionView
           viewForSupplementaryElementOfKind:(NSString *)kind
                                 atIndexPath:(NSIndexPath *)indexPath
{
    UICollectionReusableView <DTModelTransfer> *view = nil;
    id supplementary = nil;
    if ([self.storage respondsToSelector:@selector(supplementaryModelOfKind:forSectionIndex:)])
    {
        supplementary = [self.storage supplementaryModelOfKind:kind forSectionIndex:indexPath.section];
    }

    if (supplementary)
    {
        view = [self.factory supplementaryViewOfKind:kind
                                             forItem:supplementary
                                         atIndexPath:indexPath];
        [view updateWithModel:supplementary];
    }

    return view;
}

If no reusable view was registered, you will return nil. Since IOS7 it's create a crash.

[oks]

And hack with CGSizeZero - not helpful (((

[DenTelezhkin]

I don't see this behavior not in example project, not in my apps. Can you provide details, or maybe an example, when this happens?

[oks]

I don't using your project no more. Too many "intended behaviours".