General Outlook question

[pd]

Hello there. Outlook XP in a networked environment. When
viewing an email (that has an attachment)in the preview
pane, I can see the attachment icon on that little header
area between the list of emails and the previewed email.
However, when I click away to an email that is a reply to
a meeting request (that I sent out)and then click back on
the attachment-email, in the information viewer the
little attachment icon is no longer on the header.
Obviously I can still tell if the email in question has
an attachment from the information viewer. This is more
annoying more than anything else so I am just wondering
if anyone knows of some quirk in Outlook that causes
this.

Thanks in advance.