scroll knob color

[Angelo Borsotti]

Hello,

in emacs 21 and 22 running in Windows XP and also Vista
the scroll know is almost invisible in LCD monitors.
Its color is a pale gray that can hardly be seen in the
scroll bar background.
Setting the scroll-foreground and scroll-background properties
of frames has no effect. My suggestio is:

  - to change the default color so that the knob can be
    seen
  - to fix the scro-foreground and scroll-background properties
    so that the color can be customized.

Thank you

Angelo Borsotti