[web2py] IS_LIST_OF(IS_IN_SET(['A','B','C'],multiple=True)) missing drop down in form

[HP]

Hi!

I have a database model as follows

db.define_table('test',
    Field('sub_components', 'list:string', 
requires=IS_LIST_OF(IS_IN_SET(['A','B','C'],multiple=True))))

and a controller as follows:
def create():
     "creates a new component"
     form = crud.create(db.test, next=URL('index'))
     return dict(form=form)

and a view as follows:
{{extend 'layout.html'}}
<h1>Create new component</h1>
{{=form}}

This is all fine. However, he list form does not show a drop down 
selection. It validates correctly and multiple items can be added
(since it is a list) but I also want the selection drop down so the user 
can pick the valid entry. Ideas?

Thanks.
     

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