I have created a SP solution that had a list and custom action originally based on an Events list (id 106). It was asked that we change this to a new ID as per SPCAF warning (Define Type of ListTemplate greater than 10000). That is fine, but now the calendar.aspx view does not have an events tab. I Switched the custom action to use the Item's tab and all works as expected... except there is a random new group "Hierarchy" with options to Outdent, indent and show/hide subitems. I have no idea what is causing this group to appear. I cannot find it anywhere else on this list and it's views or on other lists/views.
Does anyone know how to hide this group in my SP Solution? Or alternatively, does anyone know how to use a custom template type and still get the events tab? The list template does use the events content type.