Yes, I can remove a link on the weekly roster as you have described. The difficulty is that I cannot seem to remove it as a gradeitem. When I go to
► Categories and items
► Full view
the X does not appear beside any of the Webwork problem sets.
This might seem a picayune detail, but, even with this gradeitem set to be hidden, it is still showing up on the roster of upcoming events, so a student can still mistakenly do that problem set.
At the moment, I have hidden the upcoming events box, but I don't like this and would like to just be able to remove the webwork assignment from the list of gradeitems.