There are three methods in XenForo which allow for partial class names to be used. These are: XenForo_BbCode_Formatter_Base::create XenForo_Deferred_Abstract::create XenForo_Controller->getHelper All three methods use the following line of code to check whether a partial or full class name has been used: Code: if (strpos($class, '_') === false) This follows the assumption that all full class names will contain an underscore. However, this assumption is not always correct if namespaces are used. I suggest that it be replaced with the following code: Code: if (strpos($class, '_') === false && strpos($class, '\\') === false) or something similar. Thanks.