Richard Stallman wrote:
>     Incidentally, most of the multiple X display support comes from the
>     trunk, so the bug is reproducible there as well.  It is unlikely to
>     occur in normal usage, though: the trunk does not normally disconnect
>     from an X server, while the multi-tty branch disconnects immediately
>     when the last frame is deleted. It is the act of disconnection that
>     triggers the GTK crash.
> 
> That answers my question.
> 
> One possible work-around would be not to disconnect from an X server.
> 
> Can someone change the multi-tty branch so that, when built with GTK,
> it does not try to disconnect?  Then it could support multiple X
> terminals with GTK as well as the current version does.  This obstacle
> to merging in the multi-tty branch would be gone.

I will do that.

(Disconnections can not be prevented entirely, though: Emacs/GTK crashes
on both branches if a server connection is cut or a server crashes.  In
some use cases, this happens regularly, by design: e.g., if the user
runs emacsclient to create a frame on an ssh-forwarded remote X server,
then later logs out from the ssh session, the server connection is
closed, unintentionally SEGVing the Emacs process.  I think we should
document this in PROBLEMS.)

-- 
Karoly