Add Character to Scene: List Not Populated

I have Character A, Character B and Character C in my list of characters. When I add Character A to Scene 1, then move to Scene 2, Character A does not appear in the list of available characters, until I switch away from the add-character menu and back to it. This is a bit of extra work that seems wrong.

MAC OS MOJAVE 10.14.6

STC 4.2.9

JWW