Vertical scrollbar and sliding question?

The link is here

http://www.pixel-shack.com/critter/Navigation02.html

Click on description. Move the scroll bar on the right to the bottom and then click on description again. Instead of the thumbnails scrolling up to hide the description, the main image and header move down.

Any tips on addressing this. My brains are a bit frazzled at the moment. Do I need to fix the vertical scroll position somehow. What properties do I need to be looking at?

(Note : I’m currently animating the height property of the description box.)

Second question. I did have auto margins in the wrapper centering the page. When you click on description it causes the scrollbar on the right to appear, which shifts the page over to the left. I’ve since fixed the margin, but again is there a way around this so that I can center the page again?

Many thanks.

RLM

Problem solved.