Hide overlays of children when collapsing sub process

[pinussilvestrus]

Is your feature request related to a problem? Please describe.

As described in this forum topic, when children of a sub process have overlays and the sub process get collapsed, the overlays are not getting hided as well. They keep beeing visible.

Describe the solution you'd like

Adjust the Collapse handling to hide overlays of sub process children as well.

Alternative Solutions

Let users work around this issue themselves, as described in this comment.

Additional context

Before collapsing

After collapsing

[nikku]

Workaround / implementation approach exists, cf. this comment.

[MaxTru]

Collapsing of a sub-process is not supported anymore (https://blog.camunda.com/post/2019/11/camunda-modeler-3.5.0-released/)