Thunderbird issue

Hi, I use Thunderbird 128.3.1esr. The problem appeared after I have been away from home for a week (I updated when I switched off the computer). When I click on an email in the panel that holds the list of mails, it is interpreted often as a double click, and the email instead opens in a different tab. I have then to move the mouse to the right end and close that extra tab. Once TB complained and said opening some 50 mails would take some long time, was I sure? It wanted to open the entire thread into separate tabs. Instead of listing the thread in the top panel, it thought I had requested to open them all. Only happens with Thunderbird. -- Cheers / Saludos, Carlos E. R. (from Telcontar, using openSUSE Leap 15.5)