how to keep cursor stationary when scrolling with mouse

[JohnF]

My .emacs init has
  (setq scroll-preserve-screen-position t)
  (setq scroll-conservatively 0)
  (setq auto-window-vscroll nil)
  (setq scroll-up nil)
  (setq scroll-down nil)
  (setq scroll-up-aggressively nil)
  (setq scroll-down-aggressively nil)
some of which may be unnecessary, redundant, or wrong
(I don't know elisp or exactly what I'm doing here).
But it keeps the point/cursor stationary on the screen
when scrolling with keyboard keys Page and Arrow Up/Down.
That's what I want.
    But when scrolling with the mouse, either with its
wheel or by dragging the right-hand side slider bar, the
cursor reverts to default behavior, following the text and
jumping back to center when scrolling past the page top/bottom.
    I've failed to google how to stop that. What can I put
in .emacs so that the point/cursor remains stationary on
the screen, rather than following the text, when scrolling
with the mouse? Thanks,
-- 
John Forkosh  ( mailto:  j@f.com  where j=john and f=forkosh )