Spam Filter tab disappears when checking the "Do not deliver copies of forwarded emails to the Plesk mailbox" option for a mailbox

This should be documented and underlined in the Plesk interface, on the "Edit Mailbox" screen, with a "yellow warning/info box" that will be displayed one we check this checkbox. "Forwarding messages to an email address without keeping a copy of the messages in the local mailbox disables the Spam Filter for this e-mail account."