code: def path_selection_changed(self):
          
          idx = self.currentIndex()
          if idx == SELECT_OTHER:
              external_path = self.select_directory()
              if len(external_path) > 0:
                  self.add_external_path(external_path)
                  self.setCurrentIndex(self.count() - 1)
              else:
                  self.setCurrentIndex(CWD)
          elif idx == CLEAR_LIST:
              reply = QMessageBox.question(
                      self, _("Clear other directories"),
                      _("Do you want to clear the list of other directories?"),
                      QMessageBox.Yes | QMessageBox.No)
              if reply == QMessageBox.Yes:
                  self.clear_external_paths()
              self.setCurrentIndex(CWD)
          elif idx >= EXTERNAL_PATHS:
              self.external_path = to_text_string(self.itemText(idx))
docs: Handles when the current index of the combobox changes.