Thanks, that is what I was thinking also.
They also say this:
"However keep in mind that when it comes to DVD movies there is a formatting problem to consider. Many are wider than 16:9. For example, Dances with Wolves, Tombstone, U-571, American Beauty, and Star Wars/Phantom Menace (to name a few) are all 2.35:1, not 1.78:1. So when you display these movies on a 16:9 screen you will have black bars at the top and bottom of the screen, each bar amounting to about 12% of the picture height. The bars are not as large as they would be on a 4:3 screen, but they can be visible nevertheless."
Why would the "bars" be black above/below the 16:9 source and grey on the pillars on the side of a 4:3 source. Wouldn't it be the same color (depending on the contrast of your projector)?