It seems like there has been a regression in the most recent version of Thunderbird. I vaguely remember a long, long time ago that Thunderbird did not display tool tips when hovering over images that had the title attribute defined. There was an add-on for it a long time ago that implemented that, but it appears to be dead now since the feature was implemented in the actual Thunderbird code. I only use Thunderbird as a RSS feed reader, and one of my RSS feeds is the xkcd.com comic, which famously includes a little extra tidbit about the day's comic when hovering over the image. When Thunderbird updated this morning after booting my system up, I noticed that it doesn't display the text on hover anymore. I wanted to see if other people are experiencing similar issues before opening a regression report with Mozilla. Thanks