If I understand the specification correctly, the Process on the figure 10.5 is still logically in a Pool (Participant). However, that pool’s boundary does not have to be drawn.
A Collaboration can contain two (2) or more Pools (i.e., Participants). However, a Process that represents the work performed from the point of view of the modeler or the modeler’s organization can be considered “internal” and is NOT REQUIRED to be surrounded by the boundary of the Pool, while the other Pools in the Diagram MUST have their boundary (see Figure 9.5).
Source: https://www.omg.org/spec/BPMN/2.0/PDF#page=141
Is there any reason that bpmn.io should not support this behaviour, or am I simply misreading the definition of the standard?
I think it’s just a missing feature. However, it might be difficult to implement correctly since the BpmnModeler does not know which Process represents the work performed from the point of view of the modeler or the modeler’s organization and I couldn’t find any XML property which could point us to such a Process.
We are happy to accept contributions so feel free to open a PR or an issue regarding this.