CKEditorScriptHandler::install error

"symfony/symfony": "2.8.*", "egeloen/ckeditor-bundle": "6.0.0"

An error occurs if i set in composer.json

"extra": {
    "ckeditor-clear": "skip"
}

> Ivory\CKEditorBundle\Composer\CKEditorScriptHandler::install
----------------------
| CKEditor Installer |
----------------------

  [Symfony\Component\Console\Exception\InvalidArgumentException]
  Invalid background color specified: "orange". Expected one of (black, red, green, yellow, blue, magenta, cyan, white, default)

ckeditor:install [--release [RELEASE]] [--tag [TAG]] [--clear [CLEAR]] [--exclude [EXCLUDE]] [-h|--help] [-q|--quiet] [-v|vv|vvv|--verbose] [-V|--version] [--ansi] [--no-ansi] [-n|--no-interaction] [-s|--shell] [--process-isolation] [-e|--env ENV] [--no-debug] [--] <command> [<path>]

Script Ivory\CKEditorBundle\Composer\CKEditorScriptHandler::install handling the symfony-scripts event terminated with an exception

  [RuntimeException]
  An error occurred when executing the "'ckeditor:install --clear=skip --exclude=samples --exclude=adapters'" command:
  ----------------------
  | CKEditor Installer |
  ----------------------

    [Symfony\Component\Console\Exception\InvalidArgumentException]
    Invalid background color specified: "orange". Expected one of (black, red, green, yellow, blue, magenta, cyan, white, default)

  ckeditor:install [--release [RELEASE]] [--tag [TAG]] [--clear [CLEAR]] [--exclude [EXCLUDE]] [-h|--help] [-q|--quiet] [-v|vv|vvv|--verbose] [-V|--version] [--ansi] [--no-ansi] [-n|--no-interaction] [-s|--shell] [--process-isolation]
  [-e|--env ENV] [--no-debug] [--] <command> [<path>]

install [--prefer-source] [--prefer-dist] [--dry-run] [--dev] [--no-dev] [--no-custom-installers] [--no-autoloader] [--no-scripts] [--no-progress] [--no-suggest] [-v|vv|vvv|--verbose] [-o|--optimize-autoloader] [-a|--classmap-authoritative] [--apcu-autoloader] [--ignore-platform-reqs] [--] [<packages>]...

egeloen / IvoryCKEditorBundle

CKEditorScriptHandler::install error #310