IE6-8 JS error thrown when pasting with dialog

[Jakub Ś]

I have found it when checking #8849 and #9127.

To reproduce:

1. Load the "replacebyclass" sample (important);
2. Select first line and copy/paste it. You should have 7 lines.
3. Select the bold text "sample text" in third line from the bottom;
4. Press Tab key to move focus outside of editor;
5. Click on "Paste" toolbar button; choose to deny clipboard access in order to bring up dialog.
6. Fill in the dialog with some text "abc" then click on Ok

Result: The above TC produces JS error:

Message: Invalid argument.
Line: 938
URI: /ckeditor/_source/plugins/selection/plugin.js

It has been reproducible (IE6-8) from rev. [7239] to [7382]; got fixed in [7383] and showed up again from [7447] to [7517]; got fixed in [7518] and now has been reproducible from CKEditor [7560]

Guys, Please use CRTL+F5 or clear cache from time to time if you have problems with reproducing.

[Wiktor Walc]

Simplified TC (there is no need to create 7 lines), can be constantly reproduced in IE6:

• load _samples/replacebyclass.html
• select "sample"
• press Tab to focus outside of editor
• click "Paste" button
• "Do you want to allow this page to (..)?" - answer "No"
• type abc in the Paste dialog window
• Result same as above:

   Invalid argument. Line: 938 URI: /ckeditor/_source/plugins/selection/plugin.js
  

[Wiktor Walc]

Note: in 3.6.3 I'm getting exactly the same error in the same part of code (the line number is a bit different but it's exactly the same place):

if ( sibling.nodeType == CKEDITOR.NODE_TEXT )
{
	container = sibling;
	distance -= sibling.nodeValue.length; // <----------------
}