>You need to go in the cmLookUpManager class on the form, go to the GenTagList method and put something like :-

if alias() == 'MyTable'
   This.DefineTag('Test', "DisplayExpression", , , 'LookupName')
endif

>The default code can't figure out complex index expressions. Look up GenTagList/DefineTag in the guide. This is where you need to be.

Right. Thanks Gary. I'm going to study it. I was using only the "DisplayName".

Thanks a lot for all your help.