call fireChangeViewportEvent from awt Event Thread

VadereGui/src/org/vadere/gui/onlinevisualization/model/OnlineVisualizationModel.java

 package org.vadere.gui.onlinevisualization.model;
 
+import java.awt.*;
 import java.awt.geom.Rectangle2D;
 import java.util.ArrayList;
 import java.util.Collection;
@@ -140,8 +141,12 @@ public class OnlineVisualizationModel extends SimulationModel<DefaultSimulationC
 
 			if (topography == null) {
 				topography = observationAreaSnapshot.scenario;
-				fireChangeViewportEvent(new Rectangle2D.Double(topography.getBounds().x, topography.getBounds().y,
-						topography.getBounds().width, topography.getBounds().height));
+				// recalculate GUI (fireChangeViewportEvent will synchronize on model which is also
+				// needed by some awt event. Therefore do this in EDT (Event Dispatching Thread)
+				EventQueue.invokeLater(() -> {
+					fireChangeViewportEvent(new Rectangle2D.Double(topography.getBounds().x, topography.getBounds().y,
+							topography.getBounds().width, topography.getBounds().height));
+				});
 			} else {
 				topography = observationAreaSnapshot.scenario;
 			}

VadereSimulator/src/org/vadere/simulator/control/simulation/Simulation.java

@@ -247,9 +247,9 @@ public class Simulation {
 			}
 
 			preLoop();
+			logger.info("preLoop finished.");
 
 			while (isRunSimulation) {
-
 				synchronized (this) {
 					while (isPaused) {
 						try {