Please describe the problem:
For each mail you move from one folder to another, manually or by using filters, a copy of it appears in the Trash folder.


Steps to reproduce:
1. Move a mail from folder A to B
2. Look in the Trash


Actual results:
I see my mail in the destination folder AND in the Trash

Expected results:
I would like to see the mail ONLY in the destination folder.
I would like to see the mail in the Trash folder only when I'm explicitly deleting it (manually or with a filter)

Does this happen every time?
yes

Other information:
Think to the lambda end-users that understand only what they see.