I think I found the answer in one of your other posts. Menu makes it so all following clicks are right mouse button and Address makes it so all following clicks are left mouse button. the only problem with this is that Address also brings down the console, so I have to exit that every time I go to left mouse button mode. I don't know if this is because Address is mapped to something funny, but I know ~ also brings down the console.
I guess this is something I will have to live with, but it would be nice to maybe have the mappings changed.
EDIT: Actually, it is just Beneath a Steel Sky that has the Address button mapping problem. Flight of the Amazon Queen, Monkey Island 1, and Monkey Island 2 are all unaffected. I am curious what the glitch in BASS is, though. Also, Menu and Address aren't all that convenient to be pressing all the time during a game, especially if you are left-handed.