'Shows a dialog with the help message of the config option.
:param widg: the widget who generated the signal
:param helpmsg: the message to show in the dialog'

def _showHelp(self, widg, helpmsg):

    dlg = gtk.MessageDialog(None, gtk.DIALOG_MODAL, gtk.MESSAGE_INFO, gtk.BUTTONS_OK, helpmsg)
    dlg.set_title('Plugin    help')
    dlg.run()
    dlg.destroy()
