/tmp/.ICE-unix has incorrect permissions
I believe there's a long-standing issue with permissions on /tmp/.ICE-unix on OpenIndiana.
While looking at other messages in .xsession-errors, I noticed that both my workstation and my devel VM have
_IceTransmkdir: ERROR: euid != 0,directory /tmp/.ICE-unix will not be created.
errors. Doing some research on that, it's because /tmp is a RAM-based filesystem and nothing is creating it with correct permissions, so it's being created with the permission of the first user that logs in through the GUI after a reboot. Although most GUI stuff still works, ICE considers this an error and there is apparently a performance hit for each graphical application startup, because of the incorrect permissions: http://lists.linuxfromscratch.org/pipermail/blfs-dev/2003-April/002878.html
If you web search for that error or just ".ICE-unix permissions", you'll find lots of bug reports and discussion from various Linux distros:
I've checked a few RedHat-derived systems and two Debian-derived systems, and they all are creating /tmp/.ICE-unix as root:root and mode 1777.
I believe either some part of the lightdm session startup should be enhanced to pre-create /tmp/.ICE-unix with those permissions or some other mechanism (something in svc that perhaps graphical-login depends upon?) should be used to make sure correct ownership and permissions on that directory.