def updateDatasetMenu(self):
enabled = True<EOL>current = self.vtgui.dbs_tree_view.currentIndex()<EOL>if current:<EOL><INDENT>leaf = self.vtgui.dbs_tree_model.nodeFromIndex(current)<EOL>if leaf.node_kind in ('<STR_LIT>', '<STR_LIT>'):<EOL><INDENT>enabled = False<EOL><DEDENT><DEDENT>self.plot_action.setEnabled(enabled)<EOL>
Update the `export` QAction when the Dataset menu is pulled down.

        This method is a slot. See class ctor for details.