<div class="lang">
    <div layout-xs="column" layout="row" layout-align="center">
        <div flex-xs flex-gt-xs="20" layout="column">
            <group></group>
        </div>
        <div flex-xs flex-gt-xs="40" layout="column">
            <trad></trad>
        </div>
    </div>
</div>

<div class="lang">
    <div layout-xs="column" layout="row" layout-align="center">
        <div flex-xs flex-gt-xs="20" layout="column">
            <group></group>
        </div>
        <div flex-xs flex-gt-xs="40" layout="column">
            <trad></trad>
        </div>
    </div>
    <div layout="row">
      <div flex-xs flex-gt-xs="20"></div>
      <md-button ng-click="btnBack()">
        <md-icon>reply</md-icon> Retour
      </md-button>
    </div>
</div>

Add btn back on sub page of page hub
Add btn back on sub page of page hub

