This is possible but its not nice.....
After all items in a folder all have a specific message class, you can do
either 1 off 2 things.
Create a new messageClass extension for the items to indicate that it has
been forwarded eg. IPM.Note would become IPM.Note.Forwarded. Outlook will
look for this messageClass in the registry, in order to find out if it is a
recognised filetype, and if so what to do with it ie. open inline or open
external app but also find out for the default icon for this class. So all
you have to do then is create an icon, and create the registry entry in the
HKCR / HKCU application extension location. ie. Word document is under
IPM.Word.document application extesion Word.Document.
If you want to see what is happening is suggest using regMon and watching
the appliication file extensions under HKCR, when you open a folder in
outlook, you will set it accessing each file extension and finding the
associated icon. You do not have to register a form to have this behaviour
as you want it to default to normal behaviour also when you forward / reply
etc. to the message it should maintain correct behaviour. It would be best
to change default messageclass back to IPM.Note without extension. when
copying but this may not be essential as it should default back to last form
for last known extension which is IPM.Note for an IPM.Note.Forwarded
extension.
