Before the most recent update of Thunderbird (which must have happened over night--things were fine yesterday), my email program functioned normally. I could scroll up and down within the Inbox list, and also scroll up and down within individual emails. Now, I can't see any scroll bar in either place. If I click where it used to be, a very thin bar will briefly appear, and vanish again right away. That's all I get within in an individual email. If I close the window and open it again, I will get a fatter bar in the Inbox list, and I can use it once, until I switch to another function. If I want to scroll again, I have to close the window again to get the fatter scroll bar back, again for only one use, and only within the Inbox list, never within individual emails. This is very frustrating. If anyone can help me get my email functioning again, I'd really appreciate it. Thank you.