"I create a document with Word 2007 in Windows XP Pro and save it in Word 2003
format. I open that document in OpenOffice 3 beta(linux version); I highlight
some text yellow (for instance )and save the file in Word 2003 format.  Now I
open that file in Word 2007 in Windows XP Pro.  I try removing the yellow
highlight.  I can't remove the highlight.  However, I can change the color of it."
 
I repeated the same experiment using OpenOffice 2.4 (linux) and OpenOffice 2.3
(Windows) with the same results.    

I can submit the sample Word file I used with the highlights and detailed
explanations in it. However, I do not see any option here to submit/attach a
file, which does not allow a user to follow your "issue submittal rules".