[monokitty]

Why don't the other resolutions fill the screen instead of leaving a border around the screen?

Physically impossible. If it didn't leave a border, there wouldn't be enough pixels (at lower resolutions) to go the full length of the LCD panel - in that case, the resolution (or the pixels) would stretch, making images and text completely distorted. (AFAIK.) The ratio of the other resolutions also probably aren't the WS ratio of the display itself, which would leave borders on the sides if selected (the same way WS DVD's leave top and bottom borders if watched on a non-WS (w. the same ratio) TV screen).

But... why do you want to run the 30-inch display at a lower-than-native pixel resolution?