How to get a dialog to show a list of elements

[t-chiang]

Hello all,

I'm trying to build an operation that will let me select elements from one diagram to copy to another. I'm building it into a diagram creation operation. When I create the new diagram I'm trying to create a dialog window that allows the user to select model elements from a mother diagram to duplicate into the new diagram.

I'm trying to get this to show a much of radio points that each represent a model element from the old diagram that I want to copy to the new diagram.

Edit: I'm essentially trying to recreate this kind of dialog:

Edit2: What I'm trying to do is copy elements from my first list, which represents elements from a container, into my new container and have the elements that have been copied appear in the second list.

Any and all help would be appreciated
Thomas