After learning that the
QuickActionDefaultsHandler interface doesn't work with Lightning Experience, I tried to implement the suggestion found in the comments of this answer, which is to set the Predefined Field Values for the Email Case Action.
I was able to get the
CC Address and
BCC Address to reflect my Predefined Field Values for that action, but for some reason, the
From Address does not match the Predefined Field Value I set on the action.
From Address I predefined is the Email2Case address I have set in settings, and is verified and working. It's one of the choices when the action is rendered, but the default
FROM address still shows the logged in user email address.
Are there any other steps I need to take to default the
FROM address in a LEX Email Case Action?