diff --git a/Sim/Simulation/ISimulation.h b/Sim/Simulation/ISimulation.h
index 1460ca02eabe836c312153aaed6a0a075933fd8c..9c3095e47f983479d6aa8e2283fc1b02848d13df 100644
--- a/Sim/Simulation/ISimulation.h
+++ b/Sim/Simulation/ISimulation.h
@@ -20,15 +20,15 @@
 #include "Param/Node/INode.h"
 #include <heinz/Vectors3D.h>
 
+class Datafield;
 class IBackground;
 class IComputation;
 class ICoordSystem;
 class MultiLayer;
 class ProgressHandler;
-class Datafield;
+class ReSample;
 class SimulationOptions;
 class SimulationResult;
-class ReSample;
 
 //! Abstract base class, holds the infrastructure to run a simulation.
 //!