Just checked the mouseovers on this forum for thread titles and images and they both are working for me...
Yeah, it must be something wacky with my configuration at home. Everything's fine here on my work PC.
Edit: And FF12 seems to handle massive quantites of tabs worse than its predecessor. The firefox.exe process would usually run at about 1GB for me. As the session's "age" increased, that would steadily grow to 1.5-1.7GB, at which point it would slow to a crawl and crash.
With version 12, firefox.exe now is right at around 3GB of RAM and acting very sluggish.
Same number of tabs as before, and the process has only been open a few hours, without a whole lot of activity.
:\
Edit: And I can no longer drag&drop text from a webpage up into the address bar or the search bar.
Can't drag tabs to rearrange them either.