Outlook Mail pops up control toolbar

We have a weird one here, every time a user opens an E-mail in rich text format it pops up the control tool bar as if the system is trying to design a mail. this does not happen with plain text or HTML. Mail editor is Word 2003 and cannot be changed as it is set by system policy. If we set the system to open mails in Plain Text all is OK. It only seems to have a problem with RTF.

Mail Client is Outlook 2003/exchange server running under windows XP.

Any suggestions gratefully accepted