code: def rebuild( self ):
          navitem = self.currentItem()
          if ( navitem ):
              navitem.initialize()
          self.setUpdatesEnabled(False)
          self.scrollWidget().show()
          self._originalText = ''
          partsw = self.partsWidget()
          for button in self._buttonGroup.buttons():
              self._buttonGroup.removeButton(button)
              button.close()
              button.setParent(None)
              button.deleteLater()
          layout = partsw.layout()
          parts  = self.parts()
          button = QToolButton(partsw)
          button.setAutoRaise(True)
          button.setMaximumWidth(12)
          button.setArrowType(Qt.RightArrow)
          button.setProperty('path',          wrapVariant(''))
          button.setProperty('is_completer',  wrapVariant(True))
          last_button = button
          self._buttonGroup.addButton(button)
          layout.insertWidget(0, button)
          if ( self._navigationModel ):
              last_item = self._navigationModel.itemByPath(self.text())
              show_last =  last_item and last_item.rowCount() > 0
          else:
              show_last = False
          count = len(parts)
          for i, part in enumerate(parts):
              path = self.separator().join(parts[:i+1])
              button = QToolButton(partsw)
              button.setAutoRaise(True)
              button.setText(part)
              if ( self._navigationModel ):
                  item = self._navigationModel.itemByPath(path)
                  if ( item ):
                      button.setIcon(item.icon())
                      button.setToolButtonStyle(Qt.ToolButtonTextBesideIcon)
              button.setProperty('path',         wrapVariant(path))
              button.setProperty('is_completer', wrapVariant(False))
              self._buttonGroup.addButton(button)
              layout.insertWidget((i * 2) + 1, button)
              if ( show_last or i < (count - 1) ):
                  button = QToolButton(partsw)
                  button.setAutoRaise(True)
                  button.setMaximumWidth(12)
                  button.setArrowType(Qt.RightArrow)
                  button.setProperty('path',          wrapVariant(path))
                  button.setProperty('is_completer',  wrapVariant(True))
                  self._buttonGroup.addButton(button)
                  layout.insertWidget((i * 2) + 2, button)
                  last_button = button
          if ( self.scrollWidget().width() < partsw.width() ):
              self.scrollParts(partsw.width() - self.scrollWidget().width())
          self.setUpdatesEnabled(True)
          self.navigationChanged.emit()