ASPRunner 7.1 - Autofill

I have an application where users register their details and can then join events.
Using security that users can edit only their own details, the drop down box on the add screen correctly has only two options i.e. 'Please select' and UserID.

Unfortunately the system defaults to the UserID and the only way to invoke an autofill of details from the user registration details to the event add screen is for users to click the drop down box and change selection from UserID to 'please select', then to click drop down box again and change selection back to UserID at which point autofill works fine.
I have looked but cannot see any way of making the default 'please select' which would then only require user to click drop down box and confirm userID. Has anyone spotted how this can be achieved?