Cannot switch between two models with same abstract syntax but different concrete syntax

[BentleyJOakes]

1. Load the default icon version of the class diagram metamodel
2. Create an element of the Class type
3. Open up a new model
4. Load the UML version of the class diagram
5. Create an element of the Class type
6. When one of the models is loaded, try to load the other
7. AToMPM will crash with an empty changelog AToMPM/__worker.js:266 if( step['op'] == 'RESETM' ) TypeError: Cannot read property 'op' of undefined

Example files are here

[BentleyJOakes]

Models included in default user that exhibit this issue:

• Formalisms/Annotation/AnnotationMM.model
• Formalisms/ClassicDEVS/ClassicDEVS.model

[BentleyJOakes]

Upon discussion with Vasco:

When loading a model (new or alongside), load the concrete syntax from the second model if it is different from that already loaded.