Top 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 top shadow colors:

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

  2.  Click on the Top Shadow Color button.

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