Startbutton quickfix

src/view/StartWindow.java

@@ -29,6 +29,7 @@ public class StartWindow extends JFrame {
 		startButton.addActionListener(new AbstractAction() {
 			@Override
 			public void actionPerformed(ActionEvent arg0) {
+				if(mapList.getSelectedValue() != null)
 				engine.selectMap(mapList.getSelectedValue());
 			}
 		});