Can't Drag from NSTableView with more than one row

Question

I'm writing an app that should allow me to drag items from an NSTableView to another view (custom timeline view). This works perfectly as long as there is only one item in my NSTableView. The fist images shows one item being dragged from the table view.

However, as soon as there is more than one item in my table view I can no longer drag from it. It just selects that row. The second image shows me trying to drag from the table view with more than one item.

Is there something I need to do to enable drag from the table view?

Answer 1

SOLVED. In my pasteboardWriterForRow delegate call I was returning nil instead of a valid object.