Building a window component

Hi,
I was trying to use a scrollpane component in my fla but it was giving me a headache making my dropdown menu freeze and having extra movieclips appear on a corner in the swf. I finally found this tutorial:
http://www.flashkit.com/tutorials/Dynamic_Content/ScrollPa-tommkkat-1010/index.php
and I can use the scrollpane perfectly loading it as a swf, but I don’t understand the difference between a regular component and this from the tutorial. There’s hardly any explanation on how to modify the component’s class or however this was achieved. I’d like to accomplish the same but with a window component instead.
Anybody have an idea of how to have something similar done?
I’d like to load an swf that holds a window component that doesn’t affect the code in mine like the scrollPane tutorial I posted. Loading that file works beautifully without affecting my code but if I include any component in my library my file behaves weirdly.
Please, any help on better tutorials will be appreciated,
Jordi