Hello Everybody,
I'm using checkpointing for the first time and of course I have
immediately a problem :-(

I run a lengthy simulation via the command line and tell it to create a
checkpoint after some step.
That works fine, but when I then load this checkpoint into the GUI my
FastObjectGridPortrayal2D remains black, although everthing else seems
to be fine. I can also unpause the simulation and it runs fine, but with
a black Portrayal.

When I set a breakpoint in my setupPortrayals() function I see that
doubleValue() of FastObjectGridPortrayal2D is returning the correct
values, but the display remains black !

What could be wrong ?