CKeditor 4 IE 8 Insert Image or Link Error

[TomNM]

In IE 8 NOT in compatibility mode. Paste this content into empty editor in source mode:

<div style="text-align: center"><br />
<br />
<strong>Our Mission</strong><br />
<br />
Our Mission Our Mission Our Mission Our Mission Our Mission Our Mission ,<br />
Our Mission Our Mission Our Mission Our Mission Our Mission ,<br />
Our Mission Our Mission Our Mission Our Mission Our Mission Our Mission Our Mission Our Mission .<br />
<br />
&nbsp;</div>

Switch to wysiwyg mode.

For best reproducing, click in the editor window outside of the div at the bottom. (Cursor may appear inside the div).

Attempt to insert an image or link.

You'll get the following error.

Webpage error details

User Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.1; Trident/4.0; GTB7.4; .NET CLR 2.0.50727; .NET CLR 3.0.4506.2152; .NET CLR 3.5.30729) Timestamp: Mon, 15 Oct 2012 18:16:13 UTC

Message: 'undefined' is null or not an object Line: 673 Char: 403 Code: 0 URI: ​http://nightly-v4.ckeditor.com/3563/ckeditor.js

---

If you are in compatibility mode, you will get:

Webpage error details

User Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.1; Trident/4.0; GTB7.4; .NET CLR 2.0.50727; .NET CLR 3.0.4506.2152; .NET CLR 3.5.30729) Timestamp: Mon, 15 Oct 2012 18:17:41 UTC

Message: Invalid argument. Line: 295 Char: 475 Code: 0 URI: ​http://nightly-v4.ckeditor.com/3563/ckeditor.js

[Piotrek Koszuliński]

Not any more reproducible. Dup of #9474.