I wanted to disable/hide all unnecessary functionality from someone that is only adding/modifying some contacts. So I created a role and disabled most entries there and assigned it to this user.
Annoying is that the sales, marketing, support all show the same, and activities shows a bit more. How can I hide sales, marketing, support from this user?
The sales, marketing and support menus/submenus are not really useful in that case.
You should edit the profile of that user and uncheck Module Menu Filters in the Layout options tab.