This is rather minor. A tab linking to a page in the thread_talk: namespace is visible in certain circumstances from thread: pages. I noticed its visible when viewing non-existant thread (for example http://en.wikinews.org/w/index.php?title=Thread:Comments:Facebook_takes_down_groups_supporting_Austin_crash_pilot/Proving_a_point%3F%3F%3F/reply_(nonexist) ) and during the message presented after successfully deleting a thread.

Expected behaviour: there should be no tab linking to the thread_talk: namespace, like how it behaves when viewing an actually existent tab.

Version: unspecified
Severity: minor