title: Inaccessible QPushButton mystery
body: <p>I have a QT application. It has functioning QPushButtons that are connected to slots in my program. I am now trying to add a new button <code>myNewButton</code>, but somewhere, somehow it is not being registered.</p>
  
  <p>For an existing, working button <code>myExistingButton</code> I have the line:</p>
  
  <pre><code>connect(ui-&gt;myExistingButton, SIGNAL(clicked()), this, SLOT(Foo()));
  </code></pre>
  
  <p>I cannot simply add the line:</p>
  
  <pre><code>connect(ui-&gt;myNewButton, SIGNAL(clicked()), this, SLOT(Foo()));
  </code></pre>
  
  <p>The compilation error is:</p>
  
  <pre><code>class UI::Viewer has no member named 'myNewButton'
  </code></pre>
  
  <p>And QT Creator does not list the button as an autocomplete option for <code>ui-&gt;</code> (i.e. I haven't simply mis-spelled the name). The records for <code>myExistingButton</code> and <code>myNewButton</code> are identical apart from coordinates and naming in the ui file. What could be causing this problem?</p>