Your solution wouldn't change much my model, and maybe it migth solve the
problem. But what's really strange is this: "Node" class actually has
several subclasses apart from "A" and "B". For example, there's another
"C" subclass of "Node". To make things even more complicated, "C" is
abstract also. And then there are "D", subclass of "C", and "E", subclass
of "D". So, more or less (sorry for the crappy "ASCII art" :(
Node (abstract)
__________|__________
| |
A C (abstract)
| |
B D
|
E
So, "B" and "E" are more or less in the "same situation", but "E" nodes
are created and shown without problem.
Now I'm trying debugging the generator, although I don't really know very
well where to set the breakpoints.