>I was assuming that the desired behavior was
>

1. listbox
   >
2. not a permanent appearance of the description, but the default tooltip behavior - have to move the mouse, goes away when you do something else, etc.
   >
3. an item in the list would have to be selected - arrowed to or clicked - to change the tooltip

With that in mind, it works. Not the best thing to do, but it meets the assumed requirements.
>
>However, what I should have said was:
>
>Don't do it that way, use a 2 column combobox instead.
>
>Another problem with the tooltip is that it may hide the other information.

I think what people want to see here (and in the grid) is the behaviour like in MS Word, where tooltip with the page number appears when you use the vertical scrollbar.