1. Load http://www.californiasciencecenter.org/Exhibits/Exhibits.php 2. Make sure your browser window is short enough for the page to scroll. 3. Scroll to the bottom. 4. Hover over "General Info" or "Exhibits" in the bottom yellow bar. Result: About 80% of the time, it gets flickery and unclickable. I suspect this has something to do with the URL preview box (implemented in bug 541656), since it doesn't happen on the links that are closer to the center of the page.
V dup -- now that bug 646038 is fixed, this page behaves properly.