Hi,

it would be nice if the programmer would have the possibility to specify a custom bound area for the arrange method for a diagram.
As far as I can see, the diagam's arrange method takes the whole diagram bound plus a margin given from the layout.

Further details: Let's assume you want to create a context diagram. Then you have multiple nodes, maybe of different types, which are bound to a special area. But the areas can be connected. Nevertheless, you want to auto arrange the nodes within that area and not within the whole diagram.