[Add] Prevent for enabling/disabling default language during editing language
[Add] Prevent for disabling default language in ACP language list
Thanks for your help @nocte, again..
[Add] Prevent storing an invalid language via account / preferences
[Add] Prevent storing an invalid language via frontend language choose or id
[Fix] Style issue in acp language table
Thanks for helping @nocte
Changed /upload path to /src/addons/XenDACH/..
Thanks to @Sebastiaan for this hint.