You might also like the "Tab" key -- one of Gimp's best-kept secrets. ~d Quoting Max Rabkin :

Hi,

I spent a little time trying to optimize my Gimp experience, and in the process developed this layout modifier. Based on a Property, it places some windows in a "draw" which retracts to a narrow strip at the edge of the screen until one of the windows in it gets focus, when it opens over the underlying windows.

Hope it's useful.

--Max