YUI Problem

[ragtek]

Maybe, here are some yui coder^^


I want to center my Popup which i make like this:

function init() {
YAHOO.pmbox.myPanel = new YAHOO.widget.Panel("myPanel", { width:"500px", visible:true, draggable:true,fixedcenter:true,
			  effect:[{effect:YAHOO.widget.ContainerEffect.FADE,duration:0.5},
			   				{effect:YAHOO.widget.ContainerEffect.SLIDE,duration:0.5}] } );
YAHOO.pmbox.myPanel.center(); 
YAHOO.pmbox.myPanel.render();
		}

		YAHOO.util.Event.onDOMReady(init);

my problem is that, after load is isn't centered
when i scroll, then it goes into the middle here a video of what i mean: http://www.ragtek.org/tutorials/pmfalsch.htm