added for 12.04
A class has been added to the "dropped" portion;
nt-select-height
this defaults to 15em (about 6 lines) but you can create this class in your custom.css and set it to anything you like.
If you prefer the endless-select, without the scroll bar, then just set it to auto.
.nt-select-height{height:auto}
Cheers
Bruce