this is a comon thing beacouse ie and firefox are not compatible, so some functions wont work similiar... this hapens for many other like opra, safari, etc. to fix this you will need a new css and a modification in the page it self to be sure it wont hapen again. th modification is that you will put the 2 css files in your page. the corect css will be oped(using a little java-script) depending of the browser the user uses.