Problem with second display.

I recently bought a macbook pro, and I had my old 15 inch tft which I connected to my laptop.
The problem is that in the display preferences Leopard, shows the screen as being smaller in height than what it really is. Considerably smaller in fact, as in reality the my old screen is bigger in height than the macs' and in the preferences it is shown as smaller in height than the macs.
Here is a video that might help clarify things a bit more.
http://www.abdn.ac.uk/~u06ck5/Video-0002.mp4