title: QComboBox not rendering added items correctly
body: <p>I have strange behavior with <code>QComboBox</code>, basically I listen on currentIndexChanged signal, then based on that index a second <code>QComboBox</code> get filled from <code>QStrList</code>. My problem is the second <code>QComboBox</code> gets filled normally but not showing the text correctly until I click on item then it shows up, I use a slot to fill up the <code>QComboBox</code>.</p>
  
  <pre><code>InfoEmployer::InfoEmployer(QWidget *parent) :
      QDialog(parent),
      ui(new Ui::InfoEmployer)
  {
      ui-&gt;setupUi(this);
  
      ui-&gt;gradeCombo-&gt;addItem("");
      ui-&gt;gradeCombo-&gt;addItem("200");
      ui-&gt;gradeCombo-&gt;addItem("300");
      ui-&gt;gradeCombo-&gt;addItem("400");
      ui-&gt;gradeCombo-&gt;addItem("500");
      ui-&gt;gradeCombo-&gt;addItem("600");
      ui-&gt;gradeCombo-&gt;addItem("700");
  
      QStringList levels;
      levels &lt;&lt; "10" &lt;&lt; "20" &lt;&lt; "30" &lt;&lt; "40" &lt;&lt; "50" &lt;&lt; "60" &lt;&lt; "70" &lt;&lt; "80" &lt;&lt; "90" &lt;&lt; "100" &lt;&lt; "110" &lt;&lt; "120";
      m_levelsContainer[0] = levels;
      levels.clear();
      levels &lt;&lt; "11" &lt;&lt; "22" &lt;&lt; "33" &lt;&lt; "44" &lt;&lt; "55" &lt;&lt; "66" &lt;&lt; "77" &lt;&lt; "88" &lt;&lt; "99" &lt;&lt; "110" &lt;&lt; "120" &lt;&lt; "131";
      m_levelsContainer[1] = levels;
      levels.clear();
      levels &lt;&lt; "12" &lt;&lt; "24" &lt;&lt; "36" &lt;&lt; "48" &lt;&lt; "60" &lt;&lt; "72" &lt;&lt; "84" &lt;&lt; "96" &lt;&lt; "108" &lt;&lt; "120" &lt;&lt; "132" &lt;&lt; "144";
      m_levelsContainer[2] = levels;
      levels.clear();
      levels &lt;&lt; "13" &lt;&lt; "26" &lt;&lt; "39" &lt;&lt; "53" &lt;&lt; "66" &lt;&lt; "79" &lt;&lt; "92" &lt;&lt; "105" &lt;&lt; "118" &lt;&lt; "132" &lt;&lt; "145" &lt;&lt; "158";
      m_levelsContainer[3] = levels;
      levels.clear();
      levels &lt;&lt; "14" &lt;&lt; "29" &lt;&lt; "43" &lt;&lt; "58" &lt;&lt; "72" &lt;&lt; "86" &lt;&lt; "101" &lt;&lt; "115" &lt;&lt; "130" &lt;&lt; "144" &lt;&lt; "158" &lt;&lt; "173";
      m_levelsContainer[4] = levels;
      levels.clear();
      levels &lt;&lt; "16" &lt;&lt; "32" &lt;&lt; "47" &lt;&lt; "63" &lt;&lt; "79" &lt;&lt; "95" &lt;&lt; "110" &lt;&lt; "126" &lt;&lt; "142" &lt;&lt; "158" &lt;&lt; "173" &lt;&lt; "189";
      m_levelsContainer[5] = levels;
      levels.clear();
  
      connect(ui-&gt;gradeCombo, SIGNAL(currentIndexChanged(int)), this, SLOT(getGradeLevels(int)));
  }
  
  // The slot
      void InfoEmployer::getGradeLevels(int indx)
      {
          if(indx != 0)
          {
              ui-&gt;levelCombo-&gt;clear();
              QStringList levels = m_levelsContainer[indx - 1];
              for(int i = 0; i &lt; levels.length(); ++i)
                  ui-&gt;levelCombo-&gt;addItem(levels[i]);
          }
      }
  </code></pre>
  
  <p>Note this problem is only happen to me when I fill <code>QComboBox</code> programmatically.</p>
  
  <p><strong>UPDATE</strong></p>
  
  <p>I found that the problem is not in my code, but it is on <code>QComboBox</code>! Inserting more then 10 items on <code>QComboBox</code> make it not showing items correctly, if I insert less then or ten items all items shows up correctly. 
  My Qt verions is 5.0.2 with MinGW 4.7, please test and confirm that.</p>