Haven't figured out just what triggers this yet, but sometimes the text (if any) in the search bar becomes greyed out and then clicking in the Search box fails to put the cursor in it.
if it happens again could you take a screenshot? this doesn't sound familiar.
Dunno how helpful t will be, but sure. One's above, here's another:
--John Abbe.....2013-03-22 09:25:54 +0000
has this happened recently?
Not super-recently, but I will pay more attention to it now.