[h-e-w] Scrolling too fast in 21.1

[Scott Goldstein]

Scrolling in 21.1 is very difficult to control.  When I want to
highlight a region of text with the mouse, I click a location, move the
mouse slightly, and Emacs takes off at far too rapid a pace.  In fact,
the buffer doesn't even move until I move the mouse slightly back and
discover that nearly the entire file is highlighted.

How can I get the old scrolling behaviour back?

Thanks.

Scott