When a feature is created which enables set of references, those can only be selected and then removed one at a time. E.g. when you create a round on multiple edges, each edge is listed as a reference in the same set. If you would like to remove edges from the set, you need to right-click each one of the edges to be removed and select Remove from the pop-up menu. When you want to remove many references this takes a lot of time and effort by right-clicking each individual reference.
Idea for enhancement is to enable selecting the references in a set by using CTRL or SHIFT and then carrying out operations on selected references. This way you could select more than one reference by holding CTRL, then right-click them and select Remove from the pop-up menu.