Why my start-y="55" is not working?

I want to achieve this behavior, the search box hidden in the header until you scroll at the top, I just apply that on my html but I do not know why is not working
Ionic version: "ionic": "driftyco/ionic-bower#1.0.0-beta.14"

<ion-view title="Sports" cache-view="false" hide-back-button="true">
  <ion-nav-buttons side="left">
    <button menu-toggle="left" class="button button-icon icon ion-navicon"></button>
  <ion-nav-buttons side="right">
    <button class="button button-icon icon ion-more" ng-click="displaySportSelectionModal()"></button>

<!--Here is the start-y I am talking about-->
  <ion-content start-y="55" class="has-footer" has-footer="true">
      <div id="search-box" class="bar bar-header item-input-inset">
        <div class="item-input-wrapper">
          <i class="icon ion-ios7-search placeholder-icon"></i>
          <input type="search" placeholder="Search" ng-model="data.searchQuery">
          <i class="clear-search icon ion-ios7-close-empty" ng-click="clearSearch()"></i>
        <button class="button button-clear">

Hmm, it does seem to be broken in beta14 and in the nightly builds. Could you open an issue for this?

Done with it https://github.com/driftyco/ionic/issues/3079, just I will wait for the new released then