[ESS] Busy cursor during computation: GNU Emacs vs XEmacs

[Seth Falcon]

Hello,

When I use XEmacs (21.4 patch 12) with ESS I am able to edit other
buffers during a long R computation.  With GNU Emacs (21.2.1), I get
an hourglass cursor and have to wait until my R computation in the ESS
buffer finishes.

Is there a setting for this?  A version issue?  A fundamental
difference between XEmacs and GNU Emacs?

Thanks,

+ seth