IE9 ENTER_BR problem with AUTOGROW plugin

[maximovin]

Steps to reproduce:

1. Download CKEditor by CKBuilder with default settings, but

• Just adding Autogrow plugin to selected

2. Launching /ckeditor/samples/plugins/enterkey/enterkey.html
3. Choosing "When Enter is pressed : Break the line with a <BR>"
4. Put cursor at the end of text
5. Press "Enter"

• Expected Result: Cursor moved to the next line;
• Actual Result: Cursor stays at the same line

[Jakub Ś]

I can confirm this is happening in IE9 only when you download CKEditor standard, basic or full and autogrow plugin. I wasn't able to reproduce this in git.