[BUG] Boundary Event of a task in a Expanded Call Activity is partially hidden

[tbouffard]

Describe the bug
The boundary events of a task in a expanded call activity are displayed below the task, whereas they should be displayed on top of it to be fully visible.

To Reproduce
Steps to reproduce the behavior:

1. Go to https://cdn.statically.io/gh/process-analytics/bpmn-visualization-examples/v0.26.1/demo/load-and-navigation/index.html
2. Load the B.2.0 miwg reference file
3. The boundary event of the User Task 13 located in the "Expanded Call Activity" is below the task, so it is not fully displayed

Expected behavior
The boundary event was correctly displayed with [email protected]. The issue occurs with [email protected]

Screenshots

demo v0.26.0	demo v0.26.1

Desktop (please complete the following information):

• OS: Ubuntu 20.04
• Browser Chrome 104, Firefox 104.0

Additional context
May have been introduced in the refactoring about participants #2129.
I also did some manual tests with subprocesses and at a first glance, there is no issue. To be confirmed with new tests. I used https://github.com/process-analytics/bpmn-visualization-examples/blob/v0.26.1/bpmn-files/subprocesses.bpmn (a task with a boundary event in a subprocess included in a main subprocess)

The issue can be easily reproduced with automatic visual tests

• call activities:
  • rename the existing one into xxx..01.icons
  • add a new BPMN diagram with expanded call activity with task holding a boundary event
• subprocess:
  • in the existing diagram: add a boundary events on a task

It can be also done with unit tests about the internal Model by ensuring that the boundary events are added/placed after the other elements in the list of flownodes. AFAIK, we already have some tests about that but probably none involving expanded call activities.

[csouchet]

Good catch 👍🏻