fix

src/ui/view/MyCanvas.java

@@ -267,7 +267,7 @@ public class MyCanvas extends JPanel implements MouseListener, MouseMotionListen
 							cps.getPosition().y - (controller.getScale() / 20),
 							controller.getScale() + ((controller.getScale() / 20) * 2),
 							controller.getScale() + ((controller.getScale() / 20) * 2));
-					if(showedInformation[1]){
+					if(showedInformation[1] && cps instanceof HolonObject){
 						g2.setColor(Color.BLACK);
 						float totalEnergy = ((HolonObject) cps).getCurrentEnergyAtTimeStep(model.getCurIteration());
 						g2.drawString(Float.toString(totalEnergy), cps.getPosition().x, cps.getPosition().y - 10);