One last post before the summer, but I'll be posting again in September.
If you've accidentally deleted an email in FirstClass, you can undelete it as long as the "trash" hasn't been "emptied". I think the trash is emptied nightly.
In order to see what you've deleted, open your mailbox and choose "show deleted items" from the "View" menu. Find the message you want to undelete, right click it, and choose "Undelete".
You can then hide the deleted items by choosing that option under the view menu.
Have a good summer.