Menu bar behaviour in Firefox

First of all thank you for this theme, I really like it and it does it’s job perfectly. It’s nice and clean and simple.

That said I’m encountering an issue with the behaviour of the menu bar in Firefox, where the menu is shorter than in both Chrome and IE10 and it doesn’t follow the page when you scroll. This is both on my own blog and on your own website.

When you look at front page and see the menu in the top in Firefox, you’ll notice that it’s shorter than in both Chrome and Internet Explorer 10.

There is also an issue when you scroll, where the menu bar follows the scrolling in Chrome and Internet Explorer 10, but in Firefox the menu stays in the top.

I’ve tried looking around in the CSS files of the theme, but I haven’t been able to find out why it’s different in Firefox, but I guess it’s because it renders the menu differently than in other browsers.

Do you have any ideas where I should look to correct this behaviour? You don’t have to come up with the solution, just maybe point me in the right direction to where I have to look. Maybe it’s not in the CSS, but in some of the functions of the theme?

Sincerely,
Klaus