I have created an Overlay which is rendered in the Task Element, it can also be saved in XML thanks to this function and by creating a custom model descriptor following this example.
However, I am able to save the overlay only when I change/add some element in the BPMN Diagram, which means, the new XML for overlays is generated only after eventBus.on('elements.changed') occurs. It seems that my overlay does not get listened by that elements.changed event.
Is there a listener event that makes the modeler aware that something changed? not only with the bpmn-js Elements but also with Overlays which is my use case?