[racket] DrScheme hangs under Ubuntu 11.04?

Hi all,

I've been having some trouble running DrRacket under Ubuntu Unity, the
new default interface in the upcoming Ubuntu 11.04 'Natty'.

Specifically, the splash screen with the lambda icon appears, but when
the IDE window itself opens the entire system hangs.

I installed the 'racket' package from the ppa:plt/racket PPA (private
package archive, the official way to install unofficial programmes in
Ubuntu). It runs fine under Ubuntu with vanilla GNOME and GNOME plus
Compiz (a 3-D compositor) with default settings, but it doesn't run
under Unity. This is strange, since internally Unity is implemented as a
set of Compiz plugins.

Ubuntu 11.04 introduces a few other UI changes besides Unity, such as a
Mac-like global menu bar and a new scroll-bar widget. I've tried
disabling both, to no avail. I don't think I have any particular unusual
configurations; it should be reproducible with a default Ubuntu 11.04
beta 1 install.

I don't know how to make it print out diagnostic info; I would
appreciate instructions as to how. I haven't tried compiling from
source; I can try if people think it'd be helpful.

Ubuntu 11.04 is the current development version, currently in beta
stage. It will be released in April 2011 (hence the version number
11.04).

Thanks in advance.
-- 
Hyungrok Kim