Signavio, now part of SAP, has a comprehensive BPMN process model editor, including syntax and guideline checks. They also have a generous academic licensing program.

Support for Signavio is tied into SAP’s enormous corporate infrastructure, and at time of writing, this makes public bug reports difficult within their support databases. So this is a sharable bug report for students and other users.

In the current version of Signavio, the standard modelling guideline checks incorrectly warns that an event subprocess needs to be connected so that it “originates in a start event and leads to an end event”.

This is incorrect per the BPMN 2.0.2 specification. Section 10.2.5, p177:

An Event Sub-Process MUST NOT have any incoming or outgoing Sequence Flows.

This is actually kind of the point of event subprocesses - they hang around waiting for events to happen that aren’t part of the main control flow. The warning makes sense for other subprocesses.

Example model

BPMN model file for this example.