Three Collapsible Panels (Columns)

[don]

I'm trying to build a layout that contains three collapsible (or closable) panels. I want the open panels to automatically resize (and fill) the container. Using a layout container the east and west regions collapse, but not the center; if I close the center the east and west regions don't auto fill the center area. Any suggestions on how I can accomplish a collapsible 3-column layout with auto resize/fill?