code: def mouseMoveEvent(self, event):
          
          super(FoldingPanel, self).mouseMoveEvent(event)
          th = TextHelper(self.editor)
          line = th.line_nbr_from_position(event.pos().y())
          if line >= 0:
              block = FoldScope.find_parent_scope(
                  self.editor.document().findBlockByNumber(line-1))
              if TextBlockHelper.is_fold_trigger(block):
                  if self._mouse_over_line is None:
                      # mouse enter fold scope
                      QApplication.setOverrideCursor(
                          QCursor(Qt.PointingHandCursor))
                  if self._mouse_over_line != block.blockNumber() and \
                          self._mouse_over_line is not None:
                      # fold scope changed, a previous block was highlighter so
                      # we quickly update our highlighting
                      self._mouse_over_line = block.blockNumber()
                      self._highlight_block(block)
                  else:
                      # same fold scope, request highlight
                      self._mouse_over_line = block.blockNumber()
                      self._highlight_runner.request_job(
                          self._highlight_block, block)
                  self._highight_block = block
              else:
                  # no fold scope to highlight, cancel any pending requests
                  self._highlight_runner.cancel_requests()
                  self._mouse_over_line = None
                  QApplication.restoreOverrideCursor()
              self.repaint()
docs: Detect mouser over indicator and highlight the current scope in the
          editor (up and down decoration arround the foldable text when the mouse
          is over an indicator).
  
          :param event: event