I see. "You're doing it wrong."
Now it's 2015. Windows 10 is out and Metro is subsumed into the unified OS. There is no "Metro side." "Right click > send to > mail recipient" still does not work with the native Mail app which is visible in the Start menu accessible from the desktop, is configured with all my email accounts, and is the default for all that apply to it (so says the Default Program setting). Can I now keep "Send to:" in my head now that Metro is gone? I'd like for the "Send to:" in the context menu to "just work."