I can't actually believe this isn't something I've found searching for as an idea as it's something I use in Outlook/M365 multiple times daily at work... I love the ecosystem but the inability to compose a new message, or reply to a message and and then drag an existing email from the main inbox window into the window of the email I need to send with a "As per the attached" type response to provide evidence is mind boggling and really hurts my ability to fully migrate to the ecosystem in full. Please! :)