We have reports of verifiable behavior in Firefox 3.6.10 Windows of incorrect formatting after pressing Enter.

 

Steps to reproduce:
 
Use http://cutesoft.net/example/oncarriagereturn.aspx example and select P as break element.
Copy and paste HTML from this file

Place cursor before the line that reads "Location: Suburban..." and hit Enter

Observe that line is moved several lines below and not one line

 

It behaves correctly in IE8. Any workarounds you might suggest for Firefox users besides using IE or other browser?