TYPO3 Core

I have tried to achieve a simple filter for items and wanted filter those items by a multiselect field of types.

After submitting the form with multiple values selected following error occured:

Either "key" or "id" must be provided for f:translate
in TranslateViewHelper.php line 131

The necessary code is als following:

<?php
namespace Vendor\Theme\Domain\Model;

class Demand extends \TYPO3\CMS\Extbase\DomainObject\AbstractEntity {

    /**
     * @var \TYPO3\CMS\Extbase\Persistence\ObjectStorage<\Vendor\Theme\Domain\Model\Type>
     **/
    protected $types;

    /**
     * @param \TYPO3\CMS\Extbase\Persistence\ObjectStorage<\Vendor\Theme\Domain\Model\Type> The type of the demand
     * @return void
     */
    public function setTypes($types) {
        $this->types = $types;
    }
    /**
     * @return \TYPO3\CMS\Extbase\Persistence\ObjectStorage
     */
    public function getTypes() {
        return $this->types;
    }
}

###Search.html###

<f:form class="form" method="post" action="search" name="demand" object="{demand}">

    <f:form.select property="types" options="{types}" optionLabelField="title" optionValueField="uid" multiple="1" size="10" />

    <f:form.submit value="filter"/>
</f:form>

The problem was solved when I deactivated the admin panel:

Seems to be an unwanted lang overlay for debugging issues???