To begin with, about a small problem.
Both guests and logged in users see (1) the message “Please log in and add widgets to this column” and (2) the link “Add Widgets”. If you are logged in already, Item 1 is unnecessary. If you are a guest, Item 2 is irrelavant. It makes sense only to not-logged-in users.
My main requirement is something else. Is there a way to remove the whole, regardless of whether one is a guest, not-logged-in member or logged in member? What I have in mind is making widgets already availble for users. That is, widgets are chosen globally by the Admin for all; Users can’t and don’t have to click “Add widgets”.