title: Why is ng-disabled not working on button?
body: <p>My Plunkr: <a href="http://plnkr.co/edit/4MkenJPczFbxy5aoillL?p=preview" rel="nofollow noreferrer">http://plnkr.co/edit/4MkenJPczFbxy5aoillL?p=preview</a></p>
  
  <p><img src="https://i.stack.imgur.com/4PvGR.png" alt="enter image description here"></p>
  
  <pre><code>&lt;body ng-controller="mainCtrl as main"&gt;
  
  &lt;h1&gt;Hello Plunker!&lt;/h1&gt;
  &lt;p&gt;Button should not be disabled:&lt;/p&gt;
  
  &lt;div ng-init="main.btnDisabled = false"&gt;
      &lt;button ng-model="main.my_button"
           ng-class="{ 'btn-success' : !tc.switching, 'btn-disabled' : tc.switching }"
           disabled="main.btnDisabled"
           type="button"
           class="btn btn-info btn-sm switch-btn"&gt;My Button&lt;/button&gt;  
  &lt;/div&gt;
  </code></pre>
  
  <p></p>
  
  <p>Angular</p>
  
  <pre><code>angular.module('app').controller('mainCtrl', function($scope) {
    vm = this;
    vm.btnDisabled = false;
  });
  </code></pre>
  
  <p>I found <a href="https://stackoverflow.com/questions/20518691/angularjs-ng-disabled-directive-with-expression-is-not-working">this answer here</a>, but it didn't work in my example.</p>