Copied Message shows only Displayname in Header

I have a Problem with copied Mails.
When I copy or move a Mail out of Outlook (drag&drop) to the Desktop or any Folder the mail losses the Mailadresses in the Header. 

See the Picture below, above there ist the Mail opened directly in Outlook and below the same Mail opened from the Desktop. as you see the Mail from the Desktop won't show the Mail Adresses only the Displayname. 

How can I change this behavior? the Mail Adresses should be shown anytime. any ideas

Cheers