Some things missing in the current branch:
Going off this:
http://wiki.bluegartr.com/bg/Treasure_Hunter
Patch takes care of the following:
There is about a 1% chance of upgrade from a normal attack, and a much greater chance of TH level upgrade from Sneak or Trick Attack.
As of the December 2010 update, the effectiveness of Treasure Hunter may be increased every time the Thief successfully lands a melee attack. The damage done by Sneak Attack and Trick Attack have a greater chance of increasing the effectiveness.
I still think it is missing this, someone may want to look into it:Attacks must do damage in order to potentially upgrade Treasure Hunter effectiveness. Hits for 0 do not count.
Currently it is set to 4% on a sneak attack hit, and that's it without any sub message. I'm not sure where that number came from but I left it there.Treasure Hunter can proc on the first hit of weaponskills, but will not display any message when it does.