Tkinter Scrollbar bad behavior [re. bug #10232]

[Robert A. Lerche]

I am trying to use Tkinter to create a custom scrollable widget,
similar to a list box but with 3 Entry fields per row.  In the real
application each Entry has a separate input validation routine.

I have placed a test case file in the bug I reported:
http://bugs.python.org/issue10232

The most serious issue is the behavior on MS Windows.  In my sample
program the scroll bar slider has a problem.  When slowly moved down
it works for the first few rows but fails near the bottom of travel.
Near the bottom it rapidly generates "moveto" commands that jump
between rows 4 and 7, causing the display to flash until button 1 is
released.

This behavior does not occur on Linux -- there scrolling using the
slider is smooth top to bottom.

Terry Reedy confirmed this behavior still exists in Python 3 (I tested
in 2.7 on Windows and 2.6.2 on Linux.

He suggested I post here as there may be someone more familiar with
Tkinter who could shed some light.  Thanks in advance.