it is if I remeber correctly that is auctioneer/enchantrix (esp.latter - but they are bundeled nowdays), and maybe updaiting to their currently public release might fix the issue? (for me it occasionally is slow in the hiding but has so far always maanged to hide itself - so I'm thinking updating could be good)
http://auctioneeraddon.com/dl/#preview
btw. I use the classic suite, because I have theory it being more stable and I like the layout I can handle. ;-) (I'm oldfashoned girl into some extent)