Incorrect event label behaviour for collapsed sub-choreos

[yT0n1]

Expanded Subchoreos that contain events with labels that are not connected with any sequence flows show incorrect collapsing behaviour for labels of events. Especially if the Sub-Choreos are moved. Labels are either no longer displayed when the Sub-Choreo is re-expanded or labels show outside the collapsed Sub-Choreo. This error is inherited from BpmnJS.
Original expanded Sub:

Same Sub-Choreo after being collapsed, moved and re-expanded (no more event labels)

A different Sub-Choreo, containing one start event, after being collapsed. (Label shows on Sub-Choreo, but should be hidden):

[yT0n1]

Still an open issue in bpmn-js. See: bpmn-io/bpmn-js#945