When mentioning someone in a discussion (i.e. a channel, or thread), slack hides deactivated users when typing with `@user` auto-completion. Ripcord still shows these users.

You can still view messages/conversations from deactivated users. You just can't auto-complete mention them.

Thanks for reporting that. I've fixed this problem, and also applied it to the user name picker in the bot dialog/message action user pickers. It'll be in the next release.