Running sessions are no longer closed as if paused. brindle could treat a session that was still running as paused and clean it up, closing its chat and removing its worktree. That happened after a failed message delivery or a sign-in error. It now only cleans up sessions that have really stopped.
The sidebar no longer disappears. When another tmux client, such as a second terminal, was attached to a worker's session, the sidebar could jump there and vanish from your own terminal, then close along with that worker. It now stays in the session you're looking at, and brindle moves it out of a worker's window before closing or pausing that worker.