I've got some nav links that use various CSS controls to flip the background color of a table cell when the mouse is over them. (Pretty straightforward, although there is a "div" tag inside the "a" tag.) Looks fine, works fine (except in NN4, so I did a style sheet workaround). Here's the weird thing. I downloaded and installed the Alexa toolbar the other day. When browsing that site, I found the navigation links didn't work, even though hovering over them showed the correct URL in the status bar. Clicking makes the page flicker as if refreshing, but the same page reloads, NOT the one that is linked to. I thought something had broken, but I ultimately determined that when the Alexa toolbar was on, the links didn't work. If I left it in place but switched it off, the links worked fine.
I'm kind of at a loss - does anyone understand the Alexa toolbar well enough to hazard a guess as to what is going on?