Hello,
is there some official way to model a multi-select enum in the document- & form-model?
I only manage to create fields where a single value can be selected, like this:

I did find some references about multi-select on getA12, but none of those seemed to be about document & form modeling.
Nevermind, I somehow missed it. Here it is documented: GetA12 Login

Hi @tim-steep-bit, yes there is a way to model a multiselect field. If you rightclick on a group you have the option to choose a multiselect in the add section. This will add a multiselect with an enumeration field below it. You can just enter all the values in the enumeration field as usual. For the form model you have to drag the multiselect and not the “value” enumeration into a oontrol grid to display the multiselect.
Hope this helps. If you still have some question just let me know.
Hi @tim-steep-bit
yes!!! 
You can add a multiselect in the document model
This creates a repeatable group with a field “value”. You can add your enumeration values to this. I’ve used a type definition for the Bundesländer.
You can drag and drop the multiselect group into the form model and it creates a new control (just like normal).
And this has the behaviour you’re looking for.