When opening the correlation example, available from http://www.omg.org/spec/BPMN/2.0/examples/ZIP/Correlation/Buyer%20Seller/ (with the bpmn extension changed to bpmn2), there is no diagram so canvas is blank - which is fine.

In the properties view, associated with the canvas, select the Advanced tab and scroll down to the Correlation Properties, which has a marker implying that it has child nodes. However when trying to expand this node Eclipse seems to lock up, only closing down through a forced close.