When defining the headermenu of a datatable with some configurations as shown here, the onAfterColumnHide and onAfterColumnShow events are not fired, as you can see in this snippet: https://webix.com/snippet/e0632206 .
Another thing is, if I save the state of this table and try to reapply, the datatable beahaves normally (the state is set) but the columns that are hidden will shown with the eye icon in the header menu, as shown here: https://webix.com/snippet/d6201d0e
None of the behaviours described above occurs when setting headermnu to true, which will delegate to webix its creation.