Button:hover not working in Firefox

I haveing the problem that the hover is not working in Firefox! It is working in Chrome, IE 9, IE 8 and IE 7. Does somewone know this problem and how to fix it?

The CSS:

.row button span:hover { background-position : le开发者_StackOverflow中文版ft bottom; border : 1px solid #2b2b2b; }

The HTML:

<button type="submit"><span>Button</span></button>

---

It looks like the hover event isn't getting fed down to the span.

Try selecting button:hover span instead of button span:hover

Here's a JSFiddle that works okay by doing the above: http://jsfiddle.net/3j7G5/