Asp.Net CollapsiblePanelExtender

Just been playing around with asp.net extensions, after abit of tinkering I've managed to get the collapsiblePanelExtender Working. Here's the code behind, I've basically got the repeater binding to an xml document, with all the content. I've used the
collapsiblePanelExtender with the Panel to display the Information ablum information. http://www.ooteeni.co.uk/Music.aspx. One thing I can't workout is why it doesn't hide all of the contents.
The second repeater (the list of tracks) is enclosed within the Panel yet it doesn't get get hidden??
Here's the sample of the code