When setting the maxlength and using multiline, you can paste more characters than you can type!
In your demo:
- Set the maxlength to 10.
- Paste the following in the multiline textbox:
All of the lines are pasted, but this should not be possible since a new-line should count as 2 chars!
When trying to write this text with the keyboard it will stop at "4".
Tried this in both Firefox and IE11.