>
> Is it the case that you want to form a 1:1 relationship between
> the two sets?

It is a true n:m relation, there are many production steps(n) that can be
done with either one or more(m) maschines in a shop.

> As soon as a value in the lookup set is selected
> and applied to the foreign key in the main set, you want to make
> it impossible to apply *that* value to any other row in the main
> set?

Right, for the given master (production step) I con only once assign a given
maschine.

I just want to minimize possibilities for the user to do things that don't
make sense and produce error messages which come back to me eventually.
In this case, when there is a production step assigned to a certain
maschine, I don't want to offer that maschine again when a second maschine
is to be assigned for the same production step.

Since both AutoInsert and AutoEdit are turned off for the dataset of the n:m
table, I thought it does not really make sense for the LookupCombo to become
active.

It's really just a niggle and not worth to spend to much time on.
As there ar so many possibilities with IBO, I thought it might be just a
small thing to do in order to get what I wanted.

Thanks für your help.

Florian