[bug] swipe back in ios when implement a custom nar-bar

1

ionic version 1.1.0
i want to implement nav-bar for custom content, but it will disappear when you swipe back a little, not really go back and it triggered last page beforeEnter event, then my custom navbar was disappear

custom.html

<ion-nav-bar class="bar bar-positive">
<ion-nav-back-button>
    go-back
</ion-nav-back-button>
<ion-nav-title>title</ion-nav-title>
<ion-nav-buttons side="right">
    <button class="button button-icon icon" ng-click="toggleMenu()"></button>
</ion-nav-buttons>
</ion-nav-bar>

index.html

<ion-nav-bar class="bar bar-positive" align-title="center">
  <ion-nav-back-button>
  </ion-nav-back-button>
</ion-nav-bar>
<ion-nav-view></ion-nav-view>