For the life of me I cant figure this out on my beloved N900 - when talking to someone, and a second call comes in, I put the first call on hold to tell the second person I'll call them back. I then close the second call and want to continue the first call, but cannot figure out how to 'unhold' the waiting call. I eventually then end up killing it can calling both parties back.

Am I just being stupid?

ok - i'm a dope. I see the menu options include an option to activate the call again. Silly design - it should at least prompt the user to reactivate the call - or even automatically reactivate it.