IMPORTANT / TA-21 & MODULES-82 : If we open a diagram specification, a
module view is displayed. Then if we try to delete the diagram
specification openflexo crashes. The same behaviors is reproductible for
all FIBModule views.
What seems to happen is that first the diagram specification view is
notified of a delete event and delete all internal fib views. Thus all
underlying binding value change listeners are deleted. However after
that, binding value change listeners are notified for this deletion
event, and thus reevaluate their value which causes NPE.
I put a flag to be sure that the listener is not being deleted.