If you use the preview (either side or bottom) in mail, then you can respond to mail as usual as the view contains the relevant action buttons, however if you preview a calendar invite, then you have to fully open it to respond to the invite.
The appropriate action ...
If you counter a meeting invite, the entry disappears until the original chair accepts. This can mean that if you counter an invite, someone else could then invite you for a meeting during the time that you countered the 1st invite with, which can cause a conflict, particularly if the ...
Has your meeting every been "cancelled" because the required participants did not respond, do not have it on their calendar and thus forgot about it?
You cannot count on Lotus Notes filling it in as in ND8 because the other person may not even have Lotus Notes (e.g. intra ...
When replying to a Calendar invite, it would be nice to be able to add recipients to the reply, especially useful if the reply is to suggest another attendee and you would like to lt them know without havin to send a mail or copy an paste the text.