[Banshee-List] Testing for non-empty (or empty) comments

[Isaac Witmer <isaaclw gmail com>]

I would like to create a smart playlist that has all the songs that
have a comment in them.
It seems like that's something that banshee won't allow, since this
kind of smart playlist requires the "comment" field to be left empty:
"<Comment>   <is not>  <"">"

It resets and assumes that I didn't configure the query at all.

This might be related to the bug report posted here:
http://bugs.launchpad.net/ubuntu/+source/banshee/+bug/357417