[plt-scheme] Last used statement in interactive window?

I was given the advice to use the Dr. Scheme development environment instead of mzscheme in emacs, so I thought I would try it.  One thing I have become very used to in developing with emacs is being able to call up previous entries in mzscheme's interactive window.  I have not been able to figure out how to do this in Dr. Scheme.

It is a major stumbling block for me, as I can have my test cases an alt-p press away, but in Dr. Scheme when I reevaluate the top window, I lose all entries and history in the interactive window, unless I am missing something (which I hope I am).

Any help would be much appreciated, thanks

Rohan