Recently I noticed the addition of a number in a red circle in the Thunderbird icon which shows up on the Win10 task bar. I've been trying to figure out what that number could possibly mean. At first I thought it must be unread emails or something along those lines. But even when I have NO unread or new emails in any Thunderbird folder (or up on the pop server), random numbers keep appearing (and changing) on this task bar icon. I have not seen any description of what these numbers are supposed to be. Perhaps it is working as designed, but if it is supposed to be new or unread emails it is way off. Can anyone enlighten me?