Formatting fails on new lines with CKEDITOR.ENTER_BR

[Alexander Ebert]

During development we've noticed that under specific circumstances built-in formatting options are discarded in combination with ENTER_MODE.BR.

Steps to reproduce:

1. Load an empty CKEditor with CKEDITOR.ENTER_BR (the official Demo doesn't use it)
2. Enable a specific formatting option, e.g. italic
3. Write a few words
4. Hit Return, you now have the first line in italic and are ready to write in the second (empty) line
5. Disable italic, it will not only drop italic for the second line but also for the first line

This issue was confirmed for all major browsers and latest, stable versions; CKEditor 4.1.1 (revision 5a2a7e3)

[Jakub Ś]

Problem can be reproduced in Firefox, Webkit, Opera and IE10 (works fine in IE6-9) from CKEditor 3.6.3 rev. [7392]. Problem can be reproduced in both 4.x and 3.x branches.

This is in fact DUP of #9009.