title: Show a QMenu in response to right click in a QLabel, possible?
body: <p>I'm thinking in show a <code>QMenu</code> in response to user click on a <code>QLabel</code>. So I tried:</p>
  
  <p>menu.h</p>
  
  <pre><code>#ifndef MENU_H
  #define MENU_H
  
  #include &lt;QMenu&gt;
  
  class Menu : public QMenu
  {
      Q_OBJECT
  public:
      explicit Menu(QWidget *parent = 0);
  
  signals:
  
  public slots:
  };
  
  #endif // MENU_H
  </code></pre>
  
  <p>menu.cpp</p>
  
  <pre><code>#include "menu.h"
  
  Menu::Menu(QWidget *parent) :
      QMenu(parent)
  {
      addAction("Action1");
  }
  </code></pre>
  
  <p>And the code who would supposedly call show the menu:</p>
  
  <pre><code>QLabel *label = new QLabel("...");
  m_menu = new Menu;
  label-&gt;setContextMenuPolicy(Qt::CustomContextMenu);    
  connect(label, &amp;QLabel::customContextMenuRequested, m_menu, &amp;Menu::activateWindow);
  </code></pre>
  
  <p>But it's not working. Where I'm wrong?</p>