Alas! you attached spell checker in your text input area. my all effort buried due to one mistake :-(
There's no spellchecker. It's possible that you have inputted an unsupported character. If it is a large block of text you should split the text down into smaller parts - 2 or 3 short lines for each text element - then, adding each part of the text one by one will help determine where the unsupported character is.
Thanks, sorry for the confusion, the idea has been logged for consideration by our development team.