Filter dont work in input

ionic-v1
1 
<ion-header-bar class="bar bar-header item-input-inset HeaderColor SearchHeader" ng-if="showSearchHeader">
    <label class="item-input-wrapper MenuIconColor"> <i class="icon ion-search placeholder-icon MenuIconColor SearchIcon"></i>
        <input type="text" ng-model="userSearch" placeholder="Search" style="line-height:2;">
    </label>
</ion-header-bar>
            <div class="ContactList bg_white">
            	<div ng-repeat="chatUser in chatUsers | filter:userSearch">

Why this filter dont work? What I did wrong?