cmd+A with widgets

[Mark Wade]

Steps to reproduce

1. Go to ​http://ckeditor.com/demo#widgets
2. Clear out the contents of the first editor
3. Insert a "Simple Text Box"
4. Click below it
5. Press cmd+A on the keyboard

Expected result

The entire contents of the editor should highlight.

Actual result

Nothing happens.

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

Tested on Safari 9.0.3 on Mac OS X 10.11.3 (latest versions at time of report)

[Jakub Ś]

DUP of #11064.

Please see ​https://dev.ckeditor.com/ticket/12422#comment:1 for quick and good explanation of the problem.