This may be a Mac only issue (haven't had a chance to try on PC yet), but I've found that wireless Logitech mice can not be used to zoom in the game. This is for both 1.3 (or whatever latest version of IWD is) and patch 2.0. (Apologies for not trying on latest version of game but in the middle of a modded BG game (using only Tweaks) that I am trying not to overwrite.)
I guess the first question: Is this an actual issue or a mod issue?
If real issue, does anyone have any work arounds? I have a wired Logitech mouse that behaves as expected. I've tried two wireless Logitech mice that both have the same issue.