Use of undefined constant

[hyperclock]

Notice: Use of undefined constant _XOOPS_EDITOR_TINYMCE4 - assumed '_XOOPS_EDITOR_TINYMCE4' in file /class/xoopseditor/tinymce4/editor_registry.php line 3

This notice was in the backend after turning site off. Which was gone after leaving the preferences page. Going back and turing site on showed the notice as well as updating (using update button) the same message.