[Xmonad] ShellPromp slowness

[lithis]

I have noticed the same response time slowness with the
current (darcs as of today) ShellPrompt. If I hold down a
key for a couple seconds, the key continues to repeat for a
while after the key is released. Also, xmonad uses 90% of my
CPU (Pentium 4 3.40GHz) while the key is being held. This
does not occur in SshPrompt. In Xmonad 0.3, holding a key in
a ShellPrompt uses only 4% of my CPU.