Exception on DELETE key

[WebSpellChecker.net]

Steps to reproduce:

1. Open page with empty CKEditor in IE8.
2. Type any word with space ("example ")
3. Select word without space ("[example] ")
4. Press 'Bold' to make selected word bolded.
5. Press 'Bold' to remove bold style
6. Put cursor at the start of document
7. Press and hold DELETE key.

After removing of last character 'e' see the error in browser console.

[Jakub Ś]

Problem can be reproduced in IE8 and IE7 from CKEditor 3.6.1 rev. [6919]. Problem is also reproducible in 4.x branch.

JS ERROR:
Message: Invalid argument
Line: 973
URI: /ckeditor/plugins/selection/plugin.js

Other errors where this repository is mentioned: #8166, #8667, #9176.

[Frederico Caldeira Knabben]

The error is throwing at the following line, precisely:
​https://github.com/ckeditor/ckeditor-dev/blob/a609ec5/core/selection.js#L948

It happens because that space is transformed in   at some point. For some weird (typically IE) reason, that the way IE sees that text node:

So, even if that node is valid and it is present in the DOM, IE can't handle it.

Our biggest problem is that we need to count that space in the range calculations. I still don't know how to make it happen.

[Jakub Ś]

There seems to be other TCs and other repositories from which this error starts being thrown:

1. Open editor and press new page command.
2. Switch to source and paste below:

   <p>
   	<strong>dfgdg</strong> dfg <strong>dfg</strong> dfg dg <strong>dfg</strong> df <strong>gdfgdgdfgdfgdfgdfgdfg</strong></p>
   <p>
   	df <strong>gdf</strong> <strong>gdfgdfgdfgdfgdfgdf</strong> gdgdf dgf</p>
   

3. Switch to source and click outside of editor
4. Click at the beginning of text
5. Press Delete and hold it

Result Invalid Argument is thrown from CKEditor 3.5.2

---

1. Open editor and press new page command.
2. type two lines of misspelled words e.g.

   <p>
   	dfgdfg dfg dfg dfg dfg dfg dfg fdgdgdf g</p>
   <p>
   	df dfg dfg dfg dfgdfg df g</p>
   
   

3. Enable SCAYT
4. Click at the beginning of text
5. Press Delete and hold it

Result Invalid Argument is thrown from CKEditor 3.5.3 rev. [6593]

[Jakub Ś]

There is also another TC and another bug with invalid argument reported: #10584

[Jakub Ś]

Another similar one #11427.