The page contains two buttons, from twitter and from facebook.
What I\'m observing in Firefox 3.5.15 is:
The problem here is not the position, height or any other CSS, but rather the inline-block elements taking the wrong vertical alignment. The facebook element is vertial-align: top and the twitter element is vertical-align: bottom. Can all be fixed with just one line of CSS, but have to use the correct selector and !importantoverride JS applied inline styles.
iframe[style] { /* to select the outer-most element of the twitter button */
display: inline-block;
vertical-align: bottom !important;
}