function enableElement (clients, ui, bs) {

    return function (file) {

        var uiItem   = ui.getOptionIn([CLIENT_FILES_OPT, file.name]);
        var item     = uiItem.toJS();
        var enableFn = uiItem.getIn(["callbacks", "enable"]);

        if (item.active) {
            return;
        }

        ui.setOptionIn([CLIENT_FILES_OPT, item.name, "active"], true, {silent: true});

        if (enableFn) {
            enableFn.call(ui, item);
        }

        if (item.file && !item.served) {

            ui.setOptionIn([CLIENT_FILES_OPT, item.name, "served"], true, {silent: true});

            bs.serveFile(item.src, {
                type:    types[item.type],
                content: fs.readFileSync(item.file)
            });
        }

        addElement(clients, ui.getOptionIn([CLIENT_FILES_OPT, item.name]).toJS());
    };
}
Enable a element on clients
@param clients
@param ui
@param bs
@returns {Function}