Search is not too useful if you don't know what you are looking for. Users report losing track of context-unassigned items when they have forgotten to assign a context, or when a context has been inadvertently deleted.

It is a good idea to offer the option of hiding unassigned actions from the "Contexts" view. It is bound to create redundant effort, however, (and some weakening of trust / confidence in the system) if a blind patch is made compulsory.