Doesn't work for me Rated 1 out of 5 stars

Ubuntu 9.10 (Karmic Koala)
Firefox 3.5.7 (Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.1.7) Gecko/20100106 Ubuntu/9.10 (karmic) Firefox/3.5.7 GTB6)

tooltip on xkcd still disappears after ~1 sec. :-(