it would help us help you regarding your issues if you state first what you wanted to happen.
<
User types something into CB1
CB1's RowSource changes to reflect what's been entered.
>
how does this happen >> CB1's RowSource changes??
<I suppose one way to make this work would be to populate CB2 when the user Exits CB1. Would that make more sense?>
Filtering rowsource of CB2 is normally done in the afterUpdate event of the CB1.
see this link
http://www.fontstuff.com/access/acctut10.htm