JS exception on read-only editor when there is no text

[Nejc]

If I set read-only property in aspx page and editor does not contain anything, when I click inside editor, following exception happens: Unable to get value of the property 'ownerDocument': object is null or undefined.

Bug can be easily reproduced with _Samples/FirstUse.aspx if we change editor control definition to:

<CKEditor:CKEditorControl ID="CKEditor1" ReadOnly="true" runat="server" Height="200" BasePath="~/ckeditor" />

Using CKEditor for ASP.Net 3.6.4.

[Nejc]

Forgot to mention I'm using IE9.

[Nejc]

After upgrading to version 4.1 issue is still present. Tested on IE9 and IE10.

[Jakub Ś]

I can confirm this is happening in IE8-10 (IE7 works fine). Problem can be reproduced from CKE 3.6.3 rev. [7374] in plain CKEditor as well (ASP.NET is not required to reproduce).

JS error:
Message: SCRIPT5007: Unable to get value of the property 'ownerDocument': object is null or undefined.
Line: 370
URI: /ckeditor/core/selection.js

[Jakub Ś]

This is in fact DUP of #9780