Well there is no stright Way to do this.. but you can perform with a little hack..
actually this is what is been done in flash also..(if i am right .. i did this few years back)
Create you plugin size of the sixe you want..
then on the click event of your button expand the plugin till the length of your list height..
because either you do these things in FLASH or Silver light..
then inner contetns need a framework to work..
and if your contetn size id 100px/100px and you plugin size is 50px/50px//
so it is madatory that 50px/50px fromthe contetn wil hide...
it is just like
having a popup will 500px/500px and trying to show data of 1024px/700px withoud using Scroll bars..
you know this will never happen
so try the hack it will work in the way you want it to work.
"If this answer helps you then maek it as answered"
Ravi Kant Srivastava
(Application Developer)
Scope Technology
India/South Africa