This is a followup of MDL-30328. Was detected when running the IMS compliance tests.

It seems that recently one regression was introduced so it's impossible to uncheck (and save) any of the 3 privacy settings.

To reproduce:

1) Create one external tool activity, pointing to anywhere (but not matching any site/course tool).
2) Try to uncheck the 3 privacy settings.
3) Save and edit the form again.
4) Problem: The privacy settings remain checked.