What does the icon that shows (for a while) against the SUBJECT line of messages indicate? After some time, or perhaps following my general activity within the application or some other trigger, it seems to disappear for reasons I have yet to understand. I attach a screen clip showing four of these icons ("2025 - STILL TO REVIEW" is one of my user-created folder names.) Secondly, is the answer to the above question available already in online help for Thunderbird? If so, and since I haven't found it yet, I would be grateful to be pointed towards the relevant article. As a new user, I expect it would tell me other things that will be useful for me to learn! I am using version 146.0.1 (64-bit).