Integrated popup window

programming flash
1

I am interested in a couple of facets of the following site:

http://www.hillier.com/portfolio/

  1. When you click the “read more” arrow on the bottom right-hand part of the page, a window unfolds within the parent window. How does that work? is it just a masking operation?

  2. The photo gallery also includes two interesting embellishments to the typical photo gallery. a) the selected photo is distinguished by an orange line beneath it. b) the non-selected photos are presented at 50% alpha.

Any help on these bells & whistles will be greatly appreciated. Thanks for informative tutorials, a great site and a helpful forum.