how to make a combobox like this?

http://www.websamba.com/lily369/combobox.gif

if you want to customize the combobox component, this might help:
Customizing the ComboBox component
Otherwise, make your own component using actionscript and then you can customize it any way that you want.
I made a list in flash, so the combobox won't be harder to do.

i thought it shuld be harder so i never think to make my own combobox

but if it is really difficult to customize it ,i might try to my own one

thanks IceCold

It's a bit difficult, but definitely not hard.
And all of this you can build using only text fields and some other custom shape u made for drop down arrow.
For my list i used only 1 movieclip in the library, with a textfield inside it and attached it as many time as i wanted.
The idea is simple: first display a textfield and the arrow. When the arrow is pressed, display 3 or more textfields under the first one (make this number of displayed lines a parameter for a function).
Next thing you will have to deal with the scrollbar and highlighting overed text.
The only thing on scrolling is that instead of actually scrolling, you just display the new values in the textboxes, according to the scroll position.
If you have other questions feel free to ask.

i hope these 2 links gone work for u.
http://www.kirupa.com/developer/mx/dropdownmenu.htm
http://www.webwasp.co.uk/flash-sample-m ... /index.php

that's a dropdown menu, not a combobox.
Would do for combobox if you know you don't have more than 10-15 items, but otherwise you will need a scroller.