Click on window close button when WinLoseScreen is shown will perform as 'Quit'

src/main/java/forge/control/FControl.java

@@ -112,7 +112,12 @@ public enum FControl {
                 Singletons.getView().getFrame().setDefaultCloseOperation(
                         WindowConstants.DO_NOTHING_ON_CLOSE);
 
+                if (!Singletons.getModel().getGame().isGameOver())
                     CDock.SINGLETON_INSTANCE.concede();
+                else {
+                    Singletons.getControl().changeState(FControl.Screens.HOME_SCREEN);
+                    SOverlayUtils.hideOverlay();
+                }
             }
         };