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 ? Axel