Hello Walter,
thanks for quick reply. I mean that with the TextEditingTool. I solved it now with the validation function shown in your second link. Finer should be to disallow maxlenght while editing, for this i have to play with the TextEditingTool understand you correct. I have to dive in, because my knowledge in pure javascript is not so good. I work with TypeScript and Angular so not all examples can take one to one.