message: Get rid of a random context menu when right-clicking on the menu bar
diff: <height>505</height>
  </rect>
  </property>
  + <property name="contextMenuPolicy">
  + <enum>Qt::NoContextMenu</enum>
  + </property>
  <property name="windowTitle">
  <string>MainWindow</string>
  </property>
  <height>22</height>
  </rect>
  </property>
  + <property name="contextMenuPolicy">
  + <enum>Qt::NoContextMenu</enum>
  + </property>
  <widget class="QMenu" name="menuFile">
  <property name="title">
  <string>File</string>
  