setwindow2

setwindow2 "window cg file name"
-or-
setwindow2 #rrggbb

iEXj setwindow2 ":c;twindow2.bmp"

This modifies the appearance of the text window without deleting either it or the text log.
This command can only modify the image file or the color that was first specified in setwindow, and none of the other parameters.