BPMN - Change from interrupting escalation boundary event to non-interrupting escalation boundary event properties lost

[felix-mueller]

Reproduce:

1. Model Task
2. Place Interrupting Escalation Boundary Event on Task
3. Add Escalation Name & Code
4. Change to Non-Interrupting Escalation Boundary Event
5. Notice that all properties are gone

Expected:

1. Model Task
2. Place Interrupting Escalation Boundary Event on Task
3. Add Escalation Name & Code
4. Change to Non-Interrupting Escalation Boundary Event
5. Notice that all properties are still there

[nikku]

This has been substantially improved via 2415cf9 / bpmn-js@5.0.0-beta. All properties are now kept as expected.

Two related problems remain, I've created separate issues for them: #1463, #1464.