NSCollectionView drag n drop; Sections are ignored in the drop's IndexPath

I have a doc, xib based project. it has an NSCollectionView, which properly displays the data. including items and section headers.

I have drag n drop enabled where I can drop into the collectionView, and I generate a new object. this is NOT a reordering issue (yet)

when I drop into the collectionView, if the drop is on top of a HeaderView, the drop is canceled (before it gets to my delegate code.) But more importantly : the Header views are entirely ignored in every step of the drag and drop. the hinting, only ever shows up adjacent to a collectionViewItemView, Never below or above the section header. The drop ALWAYS has a section of zero in its index path. regardless of where the drop is.

I tried to override this behavior in both the validate drop and accept drop methods. with a great deal of frustration and struggle I discovered that I cannot compare the placement of my header views, because the frames of those views are all at the base origin point.

is this normal behavior? Has anyone else run into this? is there a fix?