Update badgeValue from AppDelegate

Question

I was able to access without problem to a particular "tab" from appDelegate with this code:

 UIStoryboard *mainStoryBoard = [UIStoryboard storyboardWithName:@"Main" bundle:nil];
    UINavigationController  *myView = [mainStoryBoard instantiateViewControllerWithIdentifier:@"mailListID"];
    if (myView.tabBarItem.tag == 999)
        [myView.tabBarItem setBadgeValue:@"100"];

and how you can see from this screenshot:

I'm able to change the value of the badge from code (into appDelegate). But the result is that into the application the value not change! Seems like something needs to be refreshed!!!

Somebody could tell me why?!?