title: QTextEdit update single QTextCharFormat
body: <p>I'm trying to update the QTextCharFormat for a single character. But it is not applied:</p>
  
  <pre><code>QTextCursor cursor(document());
  cursor.setPosition(4);
  QTextCharFormat format;
  format.setFontPointSize(sizeString.toInt());
  cursor.mergeCharFormat(format);
  qDebug() &lt;&lt; "SET POS " &lt;&lt; cursor.position() &lt;&lt; " TO " &lt;&lt; sizeString.toInt();
  
  QTextCursor cursor2(document());
  cursor.setPosition(4);
  QTextCharFormat charformat = cursor2.charFormat();
  QFont font = charformat.font();
  qDebug() &lt;&lt; " LOADED FONTSIZE: " &lt;&lt; font.pointSize();
  </code></pre>
  
  <p>Output:</p>
  
  <pre><code>SET POS  4  TO  16
   LOADED FONTSIZE:  36
  </code></pre>
  
  <p>Any idea what's missing?</p>