Ionic v4 menu only works when router-outlet has the main attribute
问题 I'm building an app with ionic v4 the first time and I want to include a side menu. For testing reasons, I first put it inside of the app.component.html but I couldn't let it swipe out or in. So I saw in the documentation, that they added the main attribute on the ion-router-outlet but as far as I read: it is not documented anywhere. I don't know, why I'd have to add this, to make it actually work. Source: https://ionicframework.com/docs/api/menu <ion-router-outlet main></ion-router-outlet>