IndexSizeError is thrown on undo

[Jakub Ś]

Problem can be reproduced in Firefox and IE9-10. To reproduce:

1. Open the “Replace textarea elements by class name” sample page.
2. Put the cursor in the editor content.
3. Control-A to select all text and then DELETE.
4. Paste in some unformatted text 3 times (I typed "this pasted in" in notepad and copied it to the clipboard).
5. Enter carriage return.
6. Paste the text in 3 more times.
7. Click undo two times.

Problem can be reproduced in Firefox from CKEditro 4.0 beta with BR_mode only.

Problem can be best reproduced in IE when BR mode is used but this isn't necessary. In IE this is issue can be reproduced from CKE 4.0.

JS error is thrown: Message: IndexSizeError: Index or size is negative or greater than the allowed amount
Line: 1942
URI: ckeditor4/core/selection.js
Code: nativeRange.setStart( range.startContainer.$, range.startOffset );

[Jakub Ś]

Other issues where IndexSizeError is mentioned: #10869, #10858, #10411, #10972.

[Piotrek Koszuliński]

Perhaps part of #10812.

[Jakub Ś]

NOTE: I wasn't able to reproduce this on latest master.

[Piotrek Koszuliński]

This issue was fixed in 4.2.1. Most likely I was right that it was a caused by #10812.