I have a macro with a user form that has 2 combo boxes in it. Currently the
second combo box contains all the possible options that could arise from the
items in the first combo box. I would like to change this so that the list
of items in the second box is driven by whichever item is chosen in the first
combo box.

I have managed to do this by splitting the user form into 2 separate boxes
(ie the user confirms choice 1 before the 2nd list of choices is shown) but
I'd prefer not to do that as the user may want to change their mind about the
first choice.

Any tips or suggestions of good reference material on the net would be
gratefully received. The 2 books I've got haven't given me any inspiration.