OK, Collapsing SubGraphs really want to collapse to the margins when there aren’t any children, so I stole a little bit of LimitedSubGraph from NodeLinkDemo (see the comments in that code). The little resize handles give the user control over the minimum dimensions of an “empty” subgraph, so I think it’s a nice feature. And it gives you an option on (2) above to set the min width/height.
I’ve added Drag-in with OnSelectionDropped.
I haven’t added drag-out. I’m not sure whether you want drag-out or “make the subgraph bigger” to be the default when you drag a node inside a subgraph.
and I’ve fixed 4.
I didn’t change the collapse to just collapse to the title width. After playing with it over the last 2 days, I’ve become pretty attached to the width staying the same, it just “feels” better.
File attached here: 20101223_100240_TitleBarSubGrap.txt