According to the Mail App 'What's New' details, it says the following:
What's new in Mail and Calendar for Windows 10
New features in the latest update:
- Send email from Outlook.com aliases
- Open & save Calendar .ics attachments in email
- See multiple upcoming events on the wide Calendar live tile
- Drag and drop calendar events to reschedule them (PC only)
- Print Month view in Calendar
- Use Mail and Calendar on HoloLens
According to the details it should work, however, it doesn't work for me. Are there any non-insiders who can clarify whether they're able to send email from an Outlook.com alias in their desktop Mail App?
It works OK for me on Windows 10 Mobile, however I'm not seeing any drop-down box in the desktop app.