Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9a1) Gecko/20051120 Firefox/1.6a1 In a game I play, certain submit buttons take a noticable amount of time to depress when clicked. This appears to be because of the background behind them. If it is removed, they work normally, if it's shrunk they speed up partially. I don't know if this is a regression or not. In 1.8 branch it seemed to work okay at first, then slow down over time. In trunk, it starts slow. I haven't tested 1.7 branch or earlier. I also haven't tested any other OSes. Somewhat reduced but not minimal testcase coming up.
The following is sufficient to crawl for me: <body background="http://images.neopets.com/games/bilgedice/woodbg.gif"></body> If I make an equivalent gif without transparency, it works fine. That makes this a dupe *** This bug has been marked as a duplicate of 255703 ***
oh, and clicking the button is slow because it triggers a reflow.