Why does "edit/filter" grey out sometimes?

Every once in a while, “edit/filter” greys out. I don’t understand under what conditions this happens. Can anyone shine a light on this?

For example, I’ll be in Write mode, working on a stave that has two voices. Like 1st and 2nd Horn. I want to move the second voice to another stave so I select the entire part and then hope to edit/filter/select 2nd voice. But “filter” is greyed out. Other times, “filter” is not greyed out.

Any insight?


No explanation, but if you go Engrave, then back to Write, it will all be sorted out. It has become a habit: (Mac) Command-3, Command-2, then the menu is back. Perhaps this will be fixed in the upcoming update.

Great. Thanks.