Fix key handling in AppView

- Now offering to menu if it has focus so that it
  can do its things. Essentially if menu is visible
  it take keys.
- Relates #807

spring-shell-core/src/main/java/org/springframework/shell/component/view/control/AppView.java

@@ -107,6 +107,11 @@ public class AppView extends BoxView {
 			}
 			return KeyHandler.resultOf(event, consumed, null);
 		};
+
+		// if menu has focus, take from there
+		if (menu != null && menu.hasFocus()) {
+			return menu.getKeyHandler();
+		}
 		KeyHandler otherHandler = main != null ? main.getKeyHandler() : super.getKeyHandler();
 		return otherHandler.thenIfNotConsumed(handler);
 	}