title: Custom Qt Widget instantiated but does not show
body: <p>In Qt Creator I've dropped a custom widget onto my form, and it looks fine, but when I compile and run, only the form's default Qt widgets (slider, label, etc) show but not the plugin's widgets.    </p>
  
  <p>In the .pro file, the include path and the LIBS+= are pointing to the widget's header directory and .lib file respectively.</p>
  
  <p>The widget does display if I progrmatically instantiate it: </p>
  
  <pre><code>cwidget *cw = new cwidget(); 
  cw-&gt;show() 
  </code></pre>
  
  <p>But this creates a new window with the widget rather than adding it to the correct position on the main window.   </p>
  
  <p>Isn't there a way to have custom widget objects in the form display automatically, just like all the qt standard widgets?</p>