Empty paragraph added on pasting in Webkit and Firefox4

[Jakub Ś]

1. Start with empty editor
2. Type some text then select it with a mouse and apply bold formatting
3. Copy text with CRTL+C
4. Text is still selected so delete it using BACKSPACE. Press backspace more than once to clean all the remainings
5. Paste the text using CRTL+V
6. Switch to source. You will see that <p>&nbsp;</p> tags were added to the beginning.
7. When you come back to WYSIWYG you will see extra empty space above the pasted text.

Issue is reproducible in Webkit and Firefox4 from CKEditor 3.5.1

[Jakub Ś]

The same TC produces different error in IE6-8 - #8012

[Jakub Ś]

Forgot to mention that Webkit also adds div around paragraph that holds bolded text.