When editing convenience keys there is "null: Popup Menu Default" shortcut displayed that can't be deleted (Error deleting Shortcut: java.lang.ArrayIndexOutOfBoundException: index -1 <=17), nor can be edited as it just creates another instance, leaving the prior null one.
Using on Curve 8900 with 5.0.461 OS (yes beta, I know).
Regards, Dejan.