TYPO3 Core

Edit constants or setup only by click on the single edit link fail with:

Fatal error: Call to a member function formWidth() on a non-object in /sysext/tstemplate/Classes/Controller/TypoScriptTemplateInformationModuleFunctionController.php on line 281
Call Stack
#    Time    Memory    Function    Location
1    0.0009    253032    {main}( )    ../index.php:0
2    0.0009    253440    call_user_func ( )    ../index.php:21
3    0.0009    253480    {closure:/var/www/t3/Web/TYPO3.CMS/typo3/index.php:18-21}( )    ../index.php:21
4    0.0895    6745824    TYPO3\CMS\Backend\Http\Application->run( )    ../index.php:20
5    0.1011    7263240    TYPO3\CMS\Core\Core\Bootstrap->handleRequest( )    ../Application.php:91
6    0.1045    7382776    TYPO3\CMS\Backend\Http\BackendModuleRequestHandler->handleRequest( )    ../Bootstrap.php:307
7    0.2185    17700528    TYPO3\CMS\Backend\Http\BackendModuleRequestHandler->dispatchModule( )    ../BackendModuleRequestHandler.php:88
8    0.2232    17771072    TYPO3\CMS\Core\Http\Dispatcher->dispatch( )    ../BackendModuleRequestHandler.php:164
9    0.3046    22583984    call_user_func_array ( )    ../Dispatcher.php:41
10    0.3046    22584208    TYPO3\CMS\Tstemplate\Controller\TypoScriptTemplateModuleController->mainAction( )    ../Dispatcher.php:41
11    0.3178    22972080    TYPO3\CMS\Tstemplate\Controller\TypoScriptTemplateModuleController->main( )    ../TypoScriptTemplateModuleController.php:304
12    0.3226    23041416    TYPO3\CMS\Backend\Module\BaseScriptClass->extObjContent( )    ../TypoScriptTemplateModuleController.php:210
13    0.3226    23042952    TYPO3\CMS\Tstemplate\Controller\TypoScriptTemplateInformationModuleFunctionController->main( )    ../BaseScriptClass.php:351