How to add a bounding box to a composite shape in Roassal 3?

I'm trying to draw a bounding box around a group of shapes. I get everything in the scene, but I don't know how to make the bounding box and the text get correctly aligned:

    c := RSCanvas new.
    text := RSGroup new.
    foo := RSLabel new text: 'foo'.
    bar := RSLabel new text: 'bar'.
    text add: foo; add: bar.
    RSVerticalLineLayout on: text.
    bound := RSShapeFactory box
        model: self;
        border: (RSBorder new width: 1; color: Color black);
        cornerRadius: 5;
        width: text encompassingRectangle width + 15;
        height: text encompassingRectangle height + 10.
    all := RSComposite new shapes: { bound. text asShape }.
    c add: all.
    c  @ RSCanvasController.
    ^ c

So here is how I did it. The missing key point was to put an RSLocation.

    c := RSCanvas new.
    text := RSGroup new.
    foo := RSLabel new text: 'foo'.
    bar := RSLabel new text: 'bar'.
    text add: foo; add: bar.
    RSVerticalLineLayout on: text.
    bound := RSShapeFactory box
        model: self;
        border: (RSBorder new width: 1; color: Color black);
        cornerRadius: 5;
        width: text encompassingRectangle width + 15;
        height: text encompassingRectangle height + 10.
    contents := text asShape.
    all := RSComposite new shapes: { bound. contents }.
    RSLocation new center; outer; stick: contents on: bound.
    c add: all.
    c  @ RSCanvasController.
    ^ c