[xgarb]

I must have been doing something wrong somewhere as now a simple function like..

    public function getWidth()
    {
        return \XLite\Core\Config::getInstance()->Tienda->myWidget->data_width;
    }

with

{if:getWidth()}width="{getWidth()}"{end:}

in the template is working perfectly.

If the option is left blank in the module settings then the whole line isn't shown.

I thought I might need something a little more complex like

    public function getWidth()
    {
        $dataWidth = \XLite\Core\Config::getInstance()->Tienda->myWidget->data_width;
	return !empty($dataWidth) ? $dataWidth : false;
    }

but it doesn't seem necessary.