In a BPMN diagram, certain connections have an explicit semantic meaning. They are exclusively invisible or embedded connections.
Such connections are automatically created and deleted if objects are moved or resized.
Changes to visual relationships between an embedding object and an embedded object trigger the automatic creation or deletion of connections. These are:
Move
Change of size
Placement of an object
Create a definition copy
Create an occurrence copy
Use of drag and drop to drag an object into a BPMN diagram (in the Explorer)