Anchor moves to right when clicking it on Firefox, using HTML5, CSS3 and HTML5Boilerplate

I am developing my first website using html5boilerplate and I'm experiencing a strange thing. When doing an anchor and clicking it, it moves to the right. This it only happens on Firefox and not o开发者_JAVA百科n Chrome, for example.

You can see an example of this with my exact CSS: http://jsfiddle.net/PuEzv/

How I can solve it?

Thank you in advance!

Its a bit late to answer, but still:

Remove or modify following code to avoid the "jumping" for all links:

#submenu a, a:active, a:visited {color:#f1f1f0; margin-left:1px; margin-right: 1px;}

To keep it enabled for #submenu, I think you muste write your css selectors like this:

#submenu a,#submenu a:active,#submenu a:visited {color:#f1f1f0; margin-left:1px; margin-right: 1px;}

I hope that helped!