reply arrow not showing up
Recently, the purple arrow that appears next to messages when they have been replied to has not been showing up. It shows for some messages and not others and sometimes it shows up but then disappears. Similarly, starred messages become unstarred without being clicked. This causes a lot of confusion for our business because we cannot be sure that we are replying to all of our clients.
ప్రత్యుత్తరాలన్నీ (1)
I have some accounts that have the same problem you see - and others that work properly. It seems to depend on the nature of the IMAP server configuration - some handle the reply/starred flags and some don't.
One workaround is to right-click a received (or any other) message, Open Message In Conversation, to see the entire thread, and check if a reply has been made.
Another option is to have the reply saved in the same folder as the original message:
https://addons.mozilla.org/en-US/thunderbird/addon/copy-sent-to-current/