Diff displays wrong username and doesn't object difference in some cases

For example do a diff between rev 1.6 and 2.1 on http://www.xwiki.org/xwiki/bin/view/Panels/Community?viewer=history&

There are 2 problems:

• It says the editor of rev 1.6 is Thomas Mortagne when it's Vincent Massol
• It doesn't show the object differences (the panel was changes in 2.1 by Thomas).