When using the setting "Hide from front end?" on a field in the Custom Fields editor the setting does not work if the field is placed within a tab.
Same applies when the attribute hide_from_front is used within code when the field also has the attribute tab set.
It is a setting in the builder only, works as its name so there isn't documentation about this. I can see the issue on my demo site and I've escalated it to the development team to fix it in the next update.
.
