Switching between two windows

So I have two windows open in my converter plugin.

One shows drfreak the other one the 3ds bike from the jmonkey demos.

The funny thing is that somehow after loading the 3ds bike suddenly drfreak appears blue.

I thought, with the exception of the background color, everything is just stored in the nodes with my renderstates.

Is there anything that can be set on a renderer that changes colors even if I render a different node?

The bike model in jME has materials with different colors, so it's possible the material state is bleeding to your other objects. This usually happens if you don't call updateRenderState() on your root node.