I thought I reported this before, but I can't find it. When you open a merchant and mouse-over an item, examine windows start flying out your butt. Soon the screen is full of them and the client says, no no more please.

After a terrible night of debugging, I think I've chased this problem down to HandleExamineInfoRequest() in client.cpp. When I open a merchant window and mouse over one of the items for the first time, I get an type = 2, which translates to "WS_ExamineInfoItemLinkRequest", which by my guess is the full Examine window popping up for said item... when it should just be the pretty mouse-over tooltip thingy like it used to be. Subsequent mouse-overs of previously popped up items do show the proper popup, and NOT the Examine window -- in fact, it never seems to return to that function after you get the first Examine.
Summoning an item to my inventory, I did the same test (mouse-over) and did not get an Examine window, but instead got a type = 0, and the simple tooltip.
I will still attempt to figure this out myself, but if any savvy developers already know what's going on (coughcough), please give me a shove so I can get back to playing with merchant items without eye abuse.