Deselected checkbox settings are not saved
- Click on Administer > Customize Data and Screens > Custom Fields.
- Choose a custom field set, more > Settings
- Choose one of the selected tickboxes and deselect.
- Re-open the settings page and observe that the checkbox is still selected
Deselected value is not saved
Deselected value is saved
- CiviCRM: Master
Confirmed on dmaster.demo.civicrm.org