For my project, I'm extending UIDragDropItem so that I can get some custom behavior on Start/Move/Release.
With 3.5.8, all worked perfectly. After upgrading to 3.7.1, the Start method is triggered but never Move/Release (confirmed with debug lines in the method).
After some debugging of NGUI code I found that the bug only occurs when "Clone On Drag" is selected. My guess is that there's something incorrect in UIDragDropItem.StartDragging()
I think I'll be able to figure this bug out on my own (and I'll report back here). Any tips are appreciated though.