Unknown icon on Inbox name in Folder pane

[FFman]

Does anyone know what this yellow/orange circle icon means attached to the Inbox name?
I can't remember seeing it before and I've used TB for well over 10 years!
I can't find it in the list. http://kb.mozillazine.org/Icons_-_Thunderbird

[tanstaafl]

I think its set if you have new messages (but is not set if you just have unread messages). I believe it only effects the session where it originally detected the new mail. For example if I see the icon in a IMAP account and exit and restart Thunderbird the icon goes away even though I didn't read any of the new mail.

Originally I think it was only used when you had new mail in a thread.

[FFman]

Thanks tanstaafl, I'll do some testing for that.

[FFman]

I sent myself an email and closed TB.
I loaded TB, the email was received and the icon did not appear.
But, as soon as I click out of TB (even just clicking the date/time in the Windows notification area) and return to TB the icon immediately appears.
It even appears just by minimizing then maximizing TB.

However, I have 3 email accounts, all POP3 and this behaviour is not consistent on all accounts.
I still wonder why I haven't seen this before in all the 10+ years using TB.
Anyway, I think I'll leave it for now.
Thanks.

[morat]

That's the new messages folder indicator image in TB91.

Reference
http://searchfox.org/comm-esr91/search? ... icator.svg

I think the devs didn't use an image in TB78.

The devs use the bottom leftmost image in TB68.

More info
http://bugzilla.mozilla.org/show_bug.cgi?id=1682065

[FFman]

Thanks morat.