JS Error throwing in focusManager when editor instance in source mode loses focus.

[Nick Willett-Jeffries]

Steps to reproduce

1. Visit ​http://nightly.ckeditor.com/17-01-19-07-07/standard/samples/
2. Open browser dev tools.
3. Switch Ckeditor instance on the page to Source mode.
4. Click anywhere on the page outside of the editor instance.

Expected result

No js errors throw.

Actual result

Uncaught TypeError: Cannot read property '$' of undefined

at window.CKEDITOR.window.CKEDITOR.dom.CKEDITOR.focusManager.f (ckeditor.js:224) at window.CKEDITOR.window.CKEDITOR.dom.CKEDITOR.focusManager.<anonymous> (ckeditor.js:225) at ckeditor.js:26

Other details (browser, OS, CKEditor version, installed plugins)

MacOS Sierra, Chrome 55.0.2883.95. This is throwing in CKeditor 4.6.2, in addition to Nightly build.

Please also see comment:5 and comment:7 for other test cases.

[Jakub Ś]

Problem can be reproduced in Chrome Win & Mac from CKEditor 4.6.2.

[Jakub Ś]

#16822 was marked as duplicate.

[Mathijs den Burger]

Another reproduction path is to use the 'divarea' plugin:

1. checkout tag 4.6.2
2. open plugins/divarea/samples/divarea.html
3. click inside the editing area to focus it
4. click the 'Source' button

This triggers the following JS error:

Uncaught TypeError: Cannot read property '$' of undefined
    at CKEDITOR.focusManager.doBlur (focusmanager.js:162)
    at CKEDITOR.focusManager.<anonymous> (focusmanager.js:180)
    at tools.js:578

[Jakub Ś]

Cannot read property 'contains' of null is thrown when tabbing through editors in sharedspace sample. Once you focus link and leave last editor, error gets thrown:

Message: Cannot read property 'contains' of null
URL: ckeditor-dev/plugins/indent/plugin.js
Line: 366

[Jakub Ś]

#16873 was marked as duplicate.