Disappearing subject line in Sent Mail?

[TheMacintoshLady]

Anyone come across this while using mail.app?

I am dragging text clippings into the message pane and to the subject 
field to save time mailing out requests, and after mail is sent, unless I 
typed by hand the subject, it looks as if it doesn't "take" and no 
subject is listed!

I find this happens a lot with other things, grab and grope and stuff 
slips out from under you, or what am I doing wrong?