On my 1.4.2 version on Windows 10, it is the same way for unpackaged app (with requireAdministrator , not requestAdministrator...)
For packaged, it seems to work with
<Capabilities>
<rescap:Capability Name="runFullTrust" />
<rescap:Capability Name="allowElevation" />
</Capabilities>
in Package.appxmanifest (I checked with Task Manager or Process Explorer) but debugging does not work.