I've never really used thieves for anything but trap springing, scouting, and the occasional knife in the kidneys, but I decided to try my hand at theft—my current playthrough is with default characters and the equipment drops have been poor. Imagine my disappointment when, after a three-day trek back to Kuldahar just for some five-finger discounting, I discovered there was no UI option for robbing shopkeepers!

The thing is, though, I know there is one. It's different from pickpocketing, and is supposed to be available to thieves in the buy/sell screen. I remember it from long ago, and I've seen images in hint guides. I've tried talking to the shopkeeper with just the thief, or as a member of the larger party, with no change. What might I be doing wrong?

As far as I remember, you cannot steal from shops in IWD.

That makes me sad. I was thinking of starting over with an optimized party, and now I think I have to. Shame that they'd all just hit 7th level.

You can pick pocket the NPCs, and some of them in Kuldahar some some sweet loot.

You can swap the characters and level new ones with console command.