function after(){
                o.useDisplay ? fly(dom).setDisplayed(FALSE) : fly(dom).hide();                  
                fly(dom).clearOpacity();  
                fly(dom).setPositioning(r.pos);
                st.width = r.width;
                st.height = r.height;
                st.fontSize = '';
                fly(dom).afterFx(o);
            }
Fades the element out while slowly expanding it in all directions.  When the effect is completed, the 
element will be hidden (visibility = 'hidden') but block elements will still take up space in the document. 
The element must be removed from the DOM using the 'remove' config option if desired.
Usage:
<pre><code>
// default
el.puff();

// common config options shown with default values
el.puff({
    easing: 'easeOut',
    duration: .5,
    remove: false,
    useDisplay: false
});
</code></pre>
@param {Object} options (optional) Object literal with any of the Fx config options
@return {Ext.Element} The Element