No idea, it works fine when I left click on the thumbnails, and tried it with both Firefox and Safari, so it's unlikely to be a browser related problem.
The link to the Intro Doc is good and its a good read but the Link to the screenshots pulls up a page with thumbnails in the left frame. If you mouse over a screen shot the pointer changes but neither Left Click or Right Click seems to bring up the actual screen shot into the Frame on the Right. What am I doing wrong?