[JannieB]

The only way I got this to work was by setting the max number of columns from 3 to 4.

I did this by adding a class in my custom module like this:

abstract class GridColumns extends \XLite\View\ItemsList\Product\Customer\Category\ACustomer implements \XLite\Base\IDecorator
{
    const GRID_COLUMNS_MAX = 4;

 protected function defineWidgetParams()
    {
        parent::defineWidgetParams();

		$this->widgetParams[static::PARAM_GRID_COLUMNS] = new \XLite\Model\WidgetParam\Set('Number of columns (for Grid mode only)', 4, true, $this->getGridColumnsRange());
				
  
    }
 
}

However this will affect all pages (which is what I wanted), not just the home page.

Jan