Improve handling of suspiciously signed/encrypted emails (multiparts)
Following up on #120 (comment 355445)
the problem is that we can currently have multiple parts which have different security status, i.e. with a valid signature and with a broken signature.
Currently, those security indicators take space in the top and it leaves wiggle room for an attacker to make the user believe a certain part has been signed although it has not been signed.
An idea is to offer a button like "show only signed parts" analogous to the remote content info bar.
Edited by Milan Crha