[imp] event invitation responses in DIMP

[Liam Hoekenga]

When I try to respond to event invitations in DIMP (1.0RC2)..
- firefox says.. "You have chosen to open ShowPreview, which is a 
text/x-json.. what should Firefox do with this file?"
- safari just opens in in a new window..

in both cases, I'm left with a file or a screen that says..

     /*-secure-{"response":false,"msgs":[],"msgs_auto":true}*/

When I try in HEAD, I see the invitation, but I'm not offered the 
opportunity to respond.

I can respond from IMP.

Ideas?

Liam