Firefox is CSS-picky

It's a good thing, though.

Sometimes, when you are creating a layout in Firefox using CSS instead of tables (good for you!), and you are choosing to use position:relative; rather than the float property, you run into a problem where, if you have multiple links side by side, Firefox only allows the very last one to be clickable, and uses their heights as a sort of invisible mask to put over the rest of the links on the line (or, to be specific, within the same block-level element).

This occurs because, somewhere in your code, you probably have a block-level element tag that is missing the positioning style definition. That is, make sure all of your block-level elements have position:relative applied; it doesn't seem to cascade in the way to make sure your page elements will always have their own space to themselves, links being clickable and all.

Hope this clears some future headaches!