Issue 17 in gpapers: Drag and dropping imported pdf to an existing collection fails

[codesite...@google.com]

Status: New
Owner: ----
Labels: Type-Defect Priority-Medium

New issue 17 by ora...@yebo.co.za: Drag and dropping imported pdf to an
existing collection fails
http://code.google.com/p/gpapers/issues/detail?id=17

What steps will reproduce the problem?
1. Create a new collection (click on green plus sign in bottom left corner).
2. Drag an already imported paper from the main window and drop it onto the
new collection.
3. Click on the new collection to view its contents.

What is the expected output? What do you see instead?
Expect to see that selected paper has been added to that collection.
Instead, the collection remains empty.

What version of the product are you using? On what operating system?
gpapers 0.5dev, Ubuntu 12.04.1 LTS

Please provide any additional information below.
Scratching under the hood, I can't seem to get
handle_left_pane_drag_data_received_event() to fire. I do see event
handlers triggering for drag and drop within the main window ("can only
reorder playlists"), and a external drag and drop of a PDF imports just
fine. I really wish I was able to offer a patch, but I'm afraid it's got
my meagre skill-set stumped. Any assistance would be greatly appreciated.