Bottom Shadow Color

  Window top and bottom shadow colors have to be
  well-matched to present the three-dimensional look of
  DECwindows Motif.  DECwindows helps you to do this by
  automatically determining top and bottom shadow colors
  when you change the window color.

  To choose your own bottom shadow colors:

  1.  Click on the Manual Shadowing button to disable
      Automatic Shadowing.

  2.  Click on the Bottom Shadow Color button.

      The Session Manager displays a color mixing dialog box.
      For more information about mixing colors, click on the
      Help button in the color mixing dialog box.