Thanks, the fix was in include/class.format.php.in safe_html method i modified the iframe allowed attributes to enable the allowfullscreen attribute'iframe=-*,height,width,type,style,allowfullscreen,src(match="`^(https?:)?//(www\.)?(youtube|dailymotion|vimeo)\.com/`i"),frameborder'.($options ? '; '.$options : ''),Thanks for your support