1, Go to Demo https://dhtmlx.com/docs/products/dhtmlxRichText/
2, Type some Chinese text, then hit enter, continue to type some Chinese text
3, Select all of the text, do not hit the delete key or backspace, just continue to type Chinese texts then will trigger the error, you can see the error in console.
but in English, seems will not trigger this error.
error is about this code:
offset: t.blocks[y].textNodes[p - 1].text.length