Implemented as "validator" which will cause that if an user presses a key that is not allowed, it will not register. Saves having to add an error message that would need to be translated to different languages. Closes #474
Implemented as "validator" which will cause that if an user presses a key that is not allowed, it will not register. Saves having to add an error message that would need to be translated to different languages. Closes #474