highway=motorway not rendered with direction arrows

[naoliv]

I was trying to debug this routing problem in JOSM:

And I really couldn't find anything wrong.

Then, cliking at the highway segments I saw that they didn't any oneway tag.
Since highway=motorway implies oneway=yes (this is what we have in ​http://wiki.openstreetmap.org/wiki/Tag:highway%3Dmotorway and it's also how the routing programs use it), JOSM should draw the direction arrows on highway=motorway with oneway!=no (different from no)

As it's now we have a highway=motorway without oneway drawn exactly like a highway=motorway + oneway=no