title: qt4 the clicked signal in the connect button doesn't trigger the settext in the label
body: <p>The app runs okay but the clicked() signal doesn't trigger the setText() of the label. Any hint why it doesn't?</p>
  <pre><code>#include &lt;QApplication&gt;
  #include &lt;QLabel&gt;
  #include &lt;QPushButton&gt;
  #include &lt;QHBoxLayout&gt;
  #include &lt;QWidget&gt;
  #include &lt;QObject&gt;
  
  int main(int argc, char *argv[])
  {
      QApplication app(argc, argv);
  
      QWidget *window = new QWidget;
  
      QLabel *label = new QLabel(&quot;hello&quot;);
      QPushButton *button = new QPushButton;
      button-&gt;setText(&quot;change&quot;);
  
      QObject::connect(button, SIGNAL(clicked()), label, SLOT(setText(&quot;&lt;h1&gt;hello&lt;/h1&gt;&quot;)));
  
      QHBoxLayout *layout = new QHBoxLayout;
      layout-&gt;addWidget(label);
      layout-&gt;addWidget(button);
      window-&gt;setLayout(layout);
  
      window-&gt;show();
  
      return app.exec();
  }
  </code></pre>