Drag and drop from Outliner 4 not working

I just tried to drag some lines from Outliner 4 into Omnifocus, but the dragged “oval” with the row count just springs back to Omnioutliner. I have no problems with Import from Outliner menu, or copy-paste (the column mapping dialog appears). How can I make the drag and drop functionality work? In the manual it says

Drag and Drop

Drag a selection of rows from an OmniOutliner document onto a project or group in OmniFocus, and they’ll become actions within that project or group with hierarchy preserved. As with the Import menu command, when you release the drag OmniFocus will ask how you’d like data in the outline’s columns to be interpreted.

That’s exactly what I try to do, but it doesn’t seem to work. (OF2, OO4, Mavericks)