We are seeing some odd behavior dragging an HTML attachment from one email over to a new message.
We are using Outlook 2016, connected to Exchange Online/Office 365 if that makes a difference.
If I receive an email that has an HTML message as an attachment, I can double click to open that attachment and it displays properly.
If I forward that email with the attachment, the recipient receives my email and the attachment and it displays properly as HTML.
If I copy the attachment (ctrl-c) and open up a new email and paste in the attachment (ctrl-v), you can open the attachment and it displays as HTML as you would expect.
BUT, if instead of copy/paste, I drag the attachment over to the new email, it converts the attachment to plain text.
Yes, the copy/paste is a workaround, but I was very used to dragging the attachment from one email to another and I'd love to have that back.
I've disabled all Add-Ins, with no change in behavior.
Office and Windows updates are all current.
Microsoft Office 365 ProPlus
Version 1708 (Build 8431.2079 Click-to-Run)
On Windows 10 Enterprise
I'd love any suggestions you have.