code: def abbreviate_tab_names_changed(self, settings, key, user_data):
          
          abbreviate_tab_names = settings.get_boolean('abbreviate-tab-names')
          self.guake.abbreviate = abbreviate_tab_names
          self.guake.recompute_tabs_titles()
docs: If the gconf var abbreviate_tab_names be changed, this method will
          be called and will update tab names.