DockWidget visibility has changed

def visibility_changed(self, enable):
        """DockWidget visibility has changed"""
        SpyderPluginWidget.visibility_changed(self, enable)
        if self.dockwidget is None:
            return
        if self.dockwidget.isWindow():
            self.dock_toolbar.show()
        else:
            self.dock_toolbar.hide()
        if enable:
            self.refresh_plugin()
        self.sig_update_plugin_title.emit()