For some reason, tooltips shown when mousing over a unit frame seem to "stick" open (i.e. not disappear when the cursor leaves the unit frame). I don't have this problem when mousing over other frames or players in the 3D world. Is this a bug or am I missing something?
I was getting the same behavior and had to stop using CowTip because of it.
This is not a Bug with PitBull. This is a general Bug and I reported it already here: http://www.wowace.com/trac/ticket/1153