Deactivating list tool for empty list gives script error

[Zoltan Koszegi]

Please load the attached file into IE9 and copy-paste its content to the CK-DEMO page and follow the steps below:

1. Click on the line beneath the list.
   
2. Left-arrow until you see 2+ lists in the Element Path. You will be at the end of the the second list element.
   
3. Press [Backspace]. -- With IE8, I got an error here.
   
4. For IE9 & IE10,
   EITHER:
   

a) Click the active list tool to turn it off -> you get listNode error.

OR

b) Press [Enter] -> you get isContextFor error.

RESULT: You get a script error dialog with the following details.

listNode error:
Error: Unable to get propert 'listNode' of undefined or bull reference

isContextFor error:
Error: Unable to get property 'isContextFor' of undefined or null reference

Note: the attached file is a valid HTML.

[Zoltan Koszegi]

test file

[Piotrek Koszuliński]

Fixed title.

[Jakub Ś]

I was able to confirm this issue.

• It has first started in CKE 3.6.3 rev. [7392]. Sub-list element on delete was changed into second element of main list. (It was happening in all IE)
• From CKE 3.6.4 rev. [7540] error was thrown when backspace key was pressed.
  Problem can be reproduced in IE9-10 till CKE 4.0 and it can be reproduced in IE7-8 till current version CKE 4.1.2. Below is JS error that is thrown:

Message : Invalid argument.
Line: 1439
URI: /ckeditor4/core/selection.js

• As mentioned above in IE9 and IE10 this behaviour has changed in CKE 4.0. After pressing Backspace you have to press Enter or List button to get other error:

Message Unable to get property 'isContextFor' of undefined or null reference
Line: 70
URI: /ckeditor4/core/command.js

I'm setting version 3.6.3 for this issue.