Sometimes when sketching the contraint and other symbols overlap resulting in the inability to select one to delete or edit. For example in the attached image an overlapping rectangular pattern symbol (which I want to edit) and a coincident symbol.
What I think could work is rotating symbols all around the common reference point in a grid so that 4 can be displayed. Once Once there is more than 4 around one reference point a new symbol appears to show that there are more than 4 symbols here. When you hover over this symbol all the symbols dropdown in a line so that you can select the one you want to operate on.