title: KnockoutJS data-bind="Visible :" with two conditions is not working
body: <p>A simple thing I am trying to workout with KnockoutJS.</p>
  
  <p>I have two <code>dropdowns</code> and a <code>textbox</code>.</p>
  
  <p><strong>What I need</strong></p>
  
  <p>If both the dropdowns are selected, then only I should get the checkbox displayed. Otherwise, the text input should not visible.</p>
  
  <p><strong>What I tried:</strong></p>
  
  <p>Here is my fiddle: <a href="https://jsfiddle.net/vikash208/z4x5meua/13/" rel="noreferrer">https://jsfiddle.net/vikash208/z4x5meua/13/</a></p>
  
  <p>I used something like this:</p>
  
  <pre><code>data-bind="visible: selectedValue &amp;&amp; selectedControl"
  </code></pre>
  
  <p>From the above, the conditions are verified as below:</p>
  
  <pre><code>IF selectedValue IS TRUE AND selectedControl IS NOT UNDEFINED
  </code></pre>
  
  <p>Kindly provide me a solution and also where I went wrong with it. I am a beginner of <code>knockoutJS</code></p>