Since the recent Lightning update I am experiencing screen tearing while scrolling through the content of emails. Jsst to be certain, I am talking about the text window in the bottom right, that displays the contents of an email after selecting it in the list above it. It does not look like the smooth scrolling is actually hurting the framerate, since it doesn't appear "choppy" or "laggy". It just tends to get a segmented look with horizontal lines, as is typical for screen synchronization issues. It does not appear with other applications using Gecko, such as the latest version of Firefox. It is also limited to just the windows that actually contain editable (and scrollable) email text, like the one you use to write a new email. The most recent update did not fix this issue for me and I have not experienced this before the aforementioned "Lightning" update. I am running Thunderbird on a reasonably powerful system: - Intel i5 4690K at stock frequency - AMD Radeon R9 280X with the latest stable graphics driver from AMD - Windows 7 64-bit version I would appreciate any suggestions, or possible solutions as this is irritating my eyes more and more.