Thunderbird RSS reader…annoying behavior!

I use Thunderbird as my RSS reader. I like the fact that it flags with an asterisk, new articles retrieved since the previous time. That way I can just concentrate on new things, and not waste my time re-reading something I already read, at least until I realize I’ve already read this. However it has a very annoying feature of opening messages that you double click on in a tab…but that’s not the problem. The problem is when you return to the article list, the stars next to the new articles are gone! Why is that a thing? Just because someone wishes additional information on an article, why would that imply they were finished reviewing new articles? So don’t double click…right? Except for some reason my single clicks are turning into double clicks recently…apparently. I don’t know why, my mouse is fairly new. And on Cinnamon there’s a mouse click sensitivity slider that doesn’t seem to make any difference slid from one end to the other. Having problems finding this setting in KDE. Many google posts point to a Settings -> System Settings -> Hardware -> Input Devices -> Mouse -> Advanced which I don’t have. Some say it’s in the Workspace section which I haven’t found either. These solutions are often highly version specific.