Issue when adding sideBar menu to an existing ionic project. Some of the elements are not showing after swapping the sidebar

[good1app]

Here is my code ....

ion-menu [content]="content" type="push" class="sidemenu">
  <ion-header>
    <ion-toolbar>
      <ion-title>Menu</ion-title>
    </ion-toolbar>
  </ion-header>
  <ion-content>
    <ion-list>
      <button ion-item>
        Home
      </button>
      <button ion-item>
        Friends
      </button>
      <button ion-item>
        Events
      </button>
      <button ion-item>
        Close Menu
      </button>
    </ion-list>
  </ion-content>
</ion-menu>

<ion-nav id="nav" #content [root]="rootPage" swipeBackEnabled="false"></ion-nav>

 Thank,