Last modified: 2014-02-12 23:47:56 UTC
Click on a filter in the watch list (e.g. http://en.m.wikipedia.org/w/index.php?title=Special:Watchlist&filter=talk) when you have no articles watched in that namespace (e.g. Talk) If the list is empty there is no indication if it was empty or if there was a bug.
https://gerrit.wikimedia.org/r/39782