I've been using Thunderbird as my Windows mail programme for a long time. Last week I installed Linux Mint, and have successfully imported my emails and settings. But when I attempt to scroll a displayed email, the display is regularly so corrupted as to be unreadable, with lines, or occasionally parts of lines, ridiculously compressed, or even missing altogether, and at other times duplicated. I've tried checking and unchecking the 'Smooth scrolling' option: but this doesn't seem to help. Other programs, including FireFox, don't seem to have this problem. Any suggestions?