GHCi on "loosing" its handles takes 100% CPU

Hi

On Windows, GHC 6.4.2, the following program:

import System.Process
main = runInteractiveCommand "ghc"

When run terminates immediately, as expected, but leaves an instance
of ghc running. The ghc process takes up 100% of the CPU time, and
seemingly does nothing.

If "ghci" is used as the argument instead of "ghc", then both ghc and
ghci are left running, with ghc on 100% CPU time.

In contrast, if hugs or Yhc or edit (or pretty much any program on my
system) is run in exactly the same way, they terminate as soon as the
main program is finished.

Is there any chance that GHC could do this too?

Thanks

Neil