xmgrace hangs on load when Unity is in 3D mode

If I launch xmgrace, it causes the entire desktop to become unresponsive (one update per 5 seconds).

If I switch to a non-graphical terminal then back it "cures" the hang until I again try to use xmgrace (open a dialogue window, close xmgrace etc.). I've found that if I log in using ubuntu 2D mode, xmgrace is responsive and X does not hang.

When I run xmgrace under strace, it appears to hang during communication with X. Even when running under ubuntu-2D mode there is a lot of EAGAIN responses on the X socket. This may be a red herring though as I have very little experience with the X protocol.

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: grace 1:5.1.22-12
ProcVersionSignature: Ubuntu 3.2.0-45.70-generic 3.2.44
Uname: Linux 3.2.0-45-generic x86_64
NonfreeKernelModules: fglrx
ApportVersion: 2.0.1-0ubuntu17.3
Architecture: amd64
Date: Tue Jun 11 10:46:42 2013
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Release amd64 (20120425)
MarkForUpload: True
ProcEnviron:
 LANGUAGE=en_GB:en
 TERM=xterm
 PATH=(custom, no user)
 LANG=en_GB.UTF-8
 SHELL=/bin/bash
SourcePackage: grace
UpgradeStatus: No upgrade log present (probably fresh install)