TYPO3 Core

hi,

it's not possible to use more than one stylsheet in the configuration of the ckeditor. The way described at http://docs.ckeditor.com/#!/api/CKEDITOR.config

config.contentsCss = '/css/mysitestyles.css';
config.contentsCss = [ '/css/mysitestyles.css', '/css/anotherfile.css' ];

does not work. It produces the error

Core: Exception handler (WEB): Uncaught TYPO3 Exception: Unexpected characters near ";" at line 11 (near "contentsCss: ["/fileadmin/Template/ext/rte_ckeditor/Resources/Public/Css/custom_contents.css" , "EXT:t3sbootstrap/Resources/Public/Styles/rte.css"];"). | Symfony\Component\Yaml\Exception\ParseException thrown in file /home/www/typo3_src-8.7.1/vendor/symfony/yaml/Inline.php in line 112.

btw.: The sytax of the offical documentation and the one which is used in Base.yaml are different - contentsCss = vs. contentsCSS : (both versions don't work).