Hello.
After changing configuration compatibility mode from 8.2 to 8.3 I have this issue - the form field event StartChoice is called only when the choice form is opened, but when I press to the choice arrow nothing happens. I used this event to save previous field value, by the matter of returning it back if the user cancels selection.
This forum is intended for cases when a problem can not be solved due to restrictions of the platform: a bug or lack of functionality.
