Outlook, right mouse click on un-opened message

[Steve]

The right mouse click on an un-opened message (in Outlook,
not Outlook Express) no longer opens a drop down menu with
one selection being 'options'. I have found
this 'options', when clicked, will show the full internet
headers for the un-opened message. I really liked this
feature. It no longer works, the right mouse click that is.

Any suggestions how to get that function back?

thanks,

Steve