Queued message lost when switching away from a busy session and back

Description:
When a session is mid-task and I type a message (which gets queued for the next turn as designed), then navigate to a different session/agent tab and later switch back to the original session, the queued message is sometimes gone rather than still waiting to send.

Current workaround: Either stay on the busy session until it's free to accept the queued message before switching away, or manually copy the queued text out and paste it back as a new prompt upon returning. Neither is reliable — just avoids losing the message.

Expected behavior: A queued message should persist regardless of which session/tab is currently focused, and still be there (and still send) when returning to the session it was queued in.