changing it to `Zikula\Module\CategoriesModule\Entity\CategoryEntity` then results in the following error:

> ContextErrorException: Notice: Indirect modification of overloaded element of Guite\KnowledgeBaseModule\Entity\TicketEntity has no effect in /Applications/MAMP/htdocs/core.git/src/lib/legacy/Zikula/Workflow.php line 210

```
[1] RuntimeException: Sorry, but an unknown error occured during the submit action. Please apply the changes again!
    at n/a
        in /Applications/MAMP/htdocs/core.git/src/modules/KnowledgeBase/Form/Handler/User/Ticket/Base/EditHandler.php line 224

    at Guite\KnowledgeBaseModule\Form\Handler\User\Ticket\Base\EditHandler->applyAction(array('commandName' => 'submit', 'commandArgument' => null))
        in /Applications/MAMP/htdocs/core.git/src/modules/KnowledgeBase/Form/Handler/User/Base/EditHandler.php line 481

    at Guite\KnowledgeBaseModule\Form\Handler\User\Base\EditHandler->handleCommand(object(Zikula_Form_View), array('commandName' => 'submit', 'commandArgument' => null))
        in /Applications/MAMP/htdocs/core.git/src/modules/KnowledgeBase/Form/Handler/User/Ticket/Base/EditHandler.php line 161

    at Guite\KnowledgeBaseModule\Form\Handler\User\Ticket\Base\EditHandler->handleCommand(object(Zikula_Form_View), array('commandName' => 'submit', 'commandArgument' => null))
        in /Applications/MAMP/htdocs/core.git/src/lib/legacy/Zikula/Form/View.php line 906

    at Zikula_Form_View->raiseEvent('handleCommand', array('commandName' => 'submit', 'commandArgument' => null))
        in /Applications/MAMP/htdocs/core.git/src/lib/legacy/Zikula/Form/Plugin/Button.php line 155

    at Zikula_Form_Plugin_Button->decodePostBackEvent(object(Zikula_Form_View))
        in /Applications/MAMP/htdocs/core.git/src/lib/legacy/Zikula/Form/View.php line 1309

    at Zikula_Form_View->decodePostBackEvent_rec(array(object(Zikula_Form_Plugin_Label), object(Zikula_Form_Plugin_TextInput), object(Zikula_Form_Plugin_Label), object(Zikula_Form_Plugin_TextInput), object(Zikula_Form_Block_Volatile), object(Zikula_Form_Plugin_Label), object(Zikula_Form_Plugin_Checkbox), object(Zikula_Form_Plugin_Button), object(Zikula_Form_Plugin_Button), object(Zikula_Form_Plugin_ValidationSummary)))
        in /Applications/MAMP/htdocs/core.git/src/lib/legacy/Zikula/Form/View.php line 1308

    at Zikula_Form_View->decodePostBackEvent_rec(array(object(Zikula_Form_Plugin_ValidationSummary), object(FormFrame)))
        in /Applications/MAMP/htdocs/core.git/src/lib/legacy/Zikula/Form/View.php line 1295

    at Zikula_Form_View->decodePostBackEvent()
        in /Applications/MAMP/htdocs/core.git/src/lib/legacy/Zikula/Form/View.php line 283

    at Zikula_Form_View->execute('User/Ticket/edit.tpl', object(EditHandler))
        in /Applications/MAMP/htdocs/core.git/src/modules/KnowledgeBase/Controller/Base/UserController.php line 366

    at Guite\KnowledgeBaseModule\Controller\Base\UserController->editAction(object(Zikula_Request_Http))
        in  line 

    at call_user_func_array(array(object(UserController), 'editAction'), array(object(Zikula_Request_Http)))
        in /Applications/MAMP/htdocs/core.git/src/lib/util/ModUtil.php line 1151

    at ModUtil::exec('GuiteKnowledgeBaseModule', 'user', 'edit', array(), false, null)
        in /Applications/MAMP/htdocs/core.git/src/lib/util/ModUtil.php line 1203

    at ModUtil::func('GuiteKnowledgeBaseModule', 'user', 'edit')
        in /Applications/MAMP/htdocs/core.git/src/lib/Zikula/Bundle/CoreBundle/EventListener/LegacyRouteListener.php line 110

    at Zikula\Bundle\CoreBundle\EventListener\LegacyRouteListener->onKernelRequest(object(GetResponseEvent), 'kernel.request', object(TraceableEventDispatcher))
        in  line 

    at call_user_func(array(object(LegacyRouteListener), 'onKernelRequest'), object(GetResponseEvent), 'kernel.request', object(TraceableEventDispatcher))
        in /Applications/MAMP/htdocs/core.git/src/vendor/symfony/symfony/src/Symfony/Component/HttpKernel/Debug/TraceableEventDispatcher.php line 388

    at Symfony\Component\HttpKernel\Debug\TraceableEventDispatcher->Symfony\Component\HttpKernel\Debug\{closure}(object(GetResponseEvent), 'kernel.request', object(Zikula_EventManager))
        in  line 

    at call_user_func(object(Closure), object(GetResponseEvent), 'kernel.request', object(Zikula_EventManager))
        in /Applications/MAMP/htdocs/core.git/src/vendor/symfony/symfony/src/Symfony/Component/EventDispatcher/EventDispatcher.php line 164

    at Symfony\Component\EventDispatcher\EventDispatcher->doDispatch(array(object(Closure), object(Closure), object(Closure), object(Closure), object(Closure), object(Closure), object(Closure), object(Closure), object(Closure), object(Closure), object(Closure)), 'kernel.request', object(GetResponseEvent))
        in /Applications/MAMP/htdocs/core.git/src/vendor/symfony/symfony/src/Symfony/Component/EventDispatcher/EventDispatcher.php line 53

    at Symfony\Component\EventDispatcher\EventDispatcher->dispatch('kernel.request', object(GetResponseEvent))
        in /Applications/MAMP/htdocs/core.git/src/vendor/symfony/symfony/src/Symfony/Component/EventDispatcher/ContainerAwareEventDispatcher.php line 167

    at Symfony\Component\EventDispatcher\ContainerAwareEventDispatcher->dispatch('kernel.request', object(GetResponseEvent), null)
        in /Applications/MAMP/htdocs/core.git/src/lib/legacy/Zikula/EventManager.php line 99

    at Zikula_EventManager->dispatch('kernel.request', object(GetResponseEvent))
        in /Applications/MAMP/htdocs/core.git/src/vendor/symfony/symfony/src/Symfony/Component/HttpKernel/Debug/TraceableEventDispatcher.php line 138

    at Symfony\Component\HttpKernel\Debug\TraceableEventDispatcher->dispatch('kernel.request', object(GetResponseEvent))
        in /Applications/MAMP/htdocs/core.git/src/vendor/symfony/symfony/src/Symfony/Component/HttpKernel/HttpKernel.php line 107

    at Symfony\Component\HttpKernel\HttpKernel->handleRaw(object(Zikula_Request_Http), '1')
        in /Applications/MAMP/htdocs/core.git/src/vendor/symfony/symfony/src/Symfony/Component/HttpKernel/HttpKernel.php line 66

    at Symfony\Component\HttpKernel\HttpKernel->handle(object(Zikula_Request_Http), '1', true)
        in /Applications/MAMP/htdocs/core.git/src/vendor/symfony/symfony/src/Symfony/Component/HttpKernel/DependencyInjection/ContainerAwareHttpKernel.php line 64

    at Symfony\Component\HttpKernel\DependencyInjection\ContainerAwareHttpKernel->handle(object(Zikula_Request_Http), '1', true)
        in /Applications/MAMP/htdocs/core.git/src/vendor/symfony/symfony/src/Symfony/Component/HttpKernel/Kernel.php line 185

    at Symfony\Component\HttpKernel\Kernel->handle(object(Zikula_Request_Http))
        in /Applications/MAMP/htdocs/core.git/src/index.php line 21
```