DAML Hub public and user context

Questions
1

Hello,

I have the following issue. I have a contract where I set the observer to the public party, so that any party can see and exercise the choices on that contract. This works very well locally but it fails on DamlHub because even if the public context can see the contract it cannot exercise the choices. The user context on the other hand cannot even see the contract.

Let me give you an example:

    template Onboarding
        with
            publicParty: Party
            operator: Party
        where
            signatory operator

            observer publicParty

            key (operator): Party

            maintainer key

            choice Public_Choice: () with
                    requestor: Party
                       controller requestor
                    do
                        return ()

Currently any party can see that contract using the publicContext (in the @daml/hub-react" module). However, I cannot Public_Choice neither from the userContext nor the publicContext. Is there a way to exercise Public_Choice (being a party different from operator) from the react api?