Dear Nick,
Please go to the file: \plugins\system\yt\yt.php and remove the code:
// Frontend
if($app->isSite()){
// Remove default mootools
unset($doc->_scripts[JURI::root(true) . '/media/system/js/core.js']);
unset($doc->_scripts[JURI::root(true) . '/media/system/js/modal.js']);
unset($doc->_scripts[JURI::root(true).'/media/system/js/caption.js']);
unset($doc->_scripts[JURI::root(true) . '/media/system/js/mootools.js']);
unset($doc->_scripts[JURI::root(true).'/media/system/js/mootools-core.js']);
unset($doc->_scripts[JURI::root(true).'/media/system/js/mootools-more.js']);
unset($doc->_styleSheets[JUri::root(true) . '/media/system/css/modal.css']);
if (isset($doc->_script) && isset($doc->_script['text/javascript']))
{
$doc->_script['text/javascript'] = preg_replace('%window\.addEvent\(\'load\',\s*function\(\)\s*{\s*new\s*JCaption\(\'img.caption\'\);\s*}\);\s*%', '', $doc->_script['text/javascript']);
$doc->_script['text/javascript'] = preg_replace('%jQuery\(window\)\.on\(\'load\'\,\s*function\(\)\s*\{\s*new\s*JCaption\(\'img\.caption\'\);\s*\}\);%', '', $doc->_script['text/javascript']);
$doc->_script['text/javascript'] = preg_replace('%window\.addEvent\(\'load\',function\(\)\{\s*\}\);%', '', $doc->_script['text/javascript']);
//remove SqueezeBox.initialize in behavior.php
$doc->_script['text/javascript'] = preg_replace('%SqueezeBox\.initialize\(\{\}\);\s*SqueezeBox\.assign\(\$\(\'a.modal\'\)\.get\(\)\, {\s*parse\:\s\'rel\'\s*\}\);%', '', $doc->_script['text/javascript']);
if (empty($doc->_script['text/javascript']))
unset($doc->_script['text/javascript']);
}
}
Thanks & regards!