Weird mouseover behavior in Chrome?

We have a heading element styled as:

<div class="sidebarHeadingFont">Operation</div>

.sidebarHeadingFont {font-family: Arial, Helvetica, sans serif; font开发者_如何转开发-size:10pt; font-weight:bold; color: #003366; }

In Chrome when you put your mouse over this element the font size increases (making the width of the element bigger) and the color changes to white. Why is this?? Doesn't do this in IE or Firefox.

Are you really, really sure you don't have any other css and/or html? Cause it sounds really, really strange..