getAddRecordButtonVisible doesn't works on a detail with Activities object

Dear colleagues,

I have a detail using activities (activities of a custom type). Those activities are created just by a DCM and I don't want users add/delete or copy new ones manually. So in the detail schema I have this code in methods section:

// Disable add button
getAddRecordButtonVisible: function() {
	return false;
},
 
// Deshabilita operaciones nuevo registro
addRecordOperationsMenuItems: function() {
	return false;
},

This works to other details, but to this detail having ACTIVITIES doesn't work, why?

Some ideas how to solve this?

Thanks in advance

Regards