Popup menu for selecting Enums in Case Structure

[GregSands]

Building on the "Path Case Selection" idea, it can be difficult to remember all of the values of an Enum when defining a case structure.  I suggest a popup menu on the case structure which lists available values for selection.  Values already defined in other cases could be greyed out, and values selected in the current case could be selectable for removing.  Perhaps it would require a heading to differentiate from selecting a case, and Ctrl-click (Ctrl-right-click?) to activate.