>> [...] a global menu bar.
> Developing a standard API [...]
> Even if you did that, would X itself need hacking to support
> transferring menu info between local servers and remote clients?

No.  The underlying mechanisms are in place (properties on windows for
data transfer, and SendEvent for notifications).  Currently, these are
used for things like cut-and-paste (see the ICCCM), but all that'd be
needed to use them for this would be defining how to use them for the
purpose.

> I know it's designed to transfer UI events to the client and UI
> updates to the server--but methinks something would have to change if
> the wm started providing an integral part of the UI (menus) for the
> app.

Not really, not at the protocol levels.

X proper is not a window system; it's a framework for building window
systems.  It ships with the pieces necessary for a rudimentary window
system, so it's not entirely fair to say that "X is not a window
system", but it's actually confusing X proper, the wire protocol and
the C bindings, with "X and the X-using stuff that ships with X".

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