'Creates and shows the configuration panel.
:param plugin_tree: The plugin tree that lists all plugins of this type
:param plugin: the plugin to configure
:param longdesc: the long description of the plugin'

def config(self, plugin_tree, plugin, longdesc):

    title = (('<b><big>' + plugin.get_name()) + '</big></b>\n\n')
    idplugin = id(plugin)
    try:
        newwidg = self.created_panels[idplugin]
    except KeyError:
        newwidg = OptionsPanel(plugin_tree, plugin, title, longdesc)
        if (not newwidg.options.options):
            newwidg = None
        self.created_panels[idplugin] = newwidg
    if (newwidg is None):
        return self.clear(title, longdesc, _('This    plugins    has    no    options    to    configure'))
    self.remove(self.widg)
    self.pack_start(newwidg, expand=True)
    self.widg = newwidg
