title: QComboBox signal not trigged
body: <p>I have checked my code several times and i still can't get why it is not working.
  I use a QComboBox connected to a slot in the class like this :</p>
  
  <pre><code>this-&gt;choixCam = new QComboBox;
  this-&gt;choixCam-&gt;addItem("Camera 1");
  this-&gt;choixCam-&gt;addItem("Camera 2");
  this-&gt;choixCam-&gt;addItem("Camera 3");
  this-&gt;choixCam-&gt;addItem("All cameras");
  QObject::connect(this-&gt;choixCam, SIGNAL(currentIndexChanged(int)), this, SLOT(this-&gt;selectCam(int)));
  </code></pre>
  
  <p>This previous part of code is defined is the constructor of my class MainWindows, called in the main. The definition in the header file is the following :</p>
  
  <pre><code>public:
      QComboBox* choixCam;
  public slots:
      void selectCam(int choixCam);
  </code></pre>
  
  <p>I tried with successfully to run the slot from another signal.</p>
  
  <p>Using the signal with QString, the signal activated(int) or trying an exemple find on the net didn't work neither. Signals/slots mecanism also work for QButton and QSpinBox.</p>
  
  <p>I am running out of idea. Some help would be very appreciate.
  Thank you.</p>