WISHLIST - Delete and read news headers

I wish I could select & delete headers from a newsgroup folder.
I wish I could read the headers I've downloaded before deciding to
download the message body.

Current behavior (Thunderbird 9.0.1) is that just selecting a header
downloads the message.  "delete" button has no effect.

Selecting one or more headers allows a popup menu that has "copy to
clipboard..." with choices under them "headers" and "message" -- but the
"headers" choice, at least, doesn't work.  Contents of my clipboard did
not change when I selected "headers".

Thanks,
avest