Comment 2 for bug 849379

I am still seeing a very similar issue, though possibly it is a different bug.
Using Unity-2d from ppa 4.14-0ubuntu1~bzr777.
To replicate:
Open LibreOffice and type something in, do not save.
Initiate a logout.
LibreOffice pops up a save or discard dialog and a warning appears that there is an app still running, with an option to cancel.
Select Cancel (on either dialog) and the panel and launcher do not re-appear.

For the record, to recover from this, Ctrl+Alt+Delete allows the logout to continue.