I have checked RTDirectedLine and it is not supposed to use the way you want. Basically RTEdge is the object you want to manipulate with.

I do not know what is the objective of your example. But there is way how you could write it.

-=-=-
| v elements models |
models := (10 to: 60 by: 1).
v := RTView new.
elements := (RTEllipse new size: #yourself; color: Color red) + RTLabel elementsOn: models.
v addAll: elements.
RTEdge buildEdgesFromObjects: models from: #yourself to: [ :i | i // 2 ] inView: v.
RTGridLayout on: elements.
elements @ RTDraggable.
v @ RTDraggableView.
v canvas color: Color black.
v open.
-=-=-

Cheers,
Juraj

On Sep 12, 2014, at 5:03 PM, kilon alios <kilon.alios@gmail.com> wrote:

> Ok here comes the first question
>
> how I change the background color of RTView ?
>
> also
>
> when I do this
>
> v := RTView new.
> shape := RTEllipse new size: 20; color: Color red. shape := shape + RTLabel.
> es := shape elementOn:'hello'. v add: es.
> line := RTDirectedLine new pointsFrom: 20@20 To: 30@30.
> es2 := line element.v add: es2.
> es @ RTDraggable.
> v @ RTDraggableView .
> v open.
>
> I am getting an error
>
> MNU Array >> element
>
> why ?
>