Firefox: Products missing

This is a weird problem that I have not seen before...

If you checkout http://www.mysticgems.co.uk/ in IE it looks okay, but if you look at it in FF (I'm using FF3) and click on any of the product categories then none of the products display? All that shows is the category title and the new products box. Also the center column is collapsing causing the right column to shift left.

The site was setup by another designer so I don't know what core files have been edited - all I have done is to clone the classic template and then edit the header (logo etc) and CSS colors. I've tried switching to the classic (default) template but it still does it?

It's driving me MAD!!!!

Any ideas on what could be causing this?

Forget it!

I've just rebooted FF and it's now working fine - I must have tweaked something in Firebug which was causing this...

My apologies - can a mod delete this please