Validating choice cells before submission always fails

[saveli]

Validating single/multiple choice cells in students' version before submission always fails with You did not provide a response., despite having selected at least one answer per choice cell.

When submitting anyways the autograder/corrector will see the chosen answers - but this behaviour will definitely make students feel insecure.

[tmetzl]

Thanks for raising the issue. We will look into the validation.