You can create a diagram and add corresponding elements there as a shortcuts
- this should be possible to achieve with current GMF state.
In addition with minor manual code/templates modifications you can represent
these elements as normal diagram elements.
Concerning non-synchronized diagrams - UI suggest you to set GenDiagram.synchronized
property to false in .gmfgen model, regenerate ode and see what's happening.
In few wordsa - once you create new domain model element in an underlying
domain model corresponding element will not appear on this diagram automatically.
Only elements created dierectly from this diagram will be there. The rest
is up to user - you can either use shortcuts to add more lements there or
use your own action for adding elements.