Re: delete-overlay causes recentering

[Richard Stallman <rms@gnu.org>]

    > If we use the original values of BEG_UNCHANGED and END_UNCHANGED,
    > before it is "updated" by the above code, the spurious recentering
    > does not take place.  The original (2006) test case also seems to
    > behave OK -- in that case, we recenter correctly.  However, I can't be
    > certain this is correct because I don't know the original
    > justification for the above check.

    Thanks a lot for looking at this, but the new behavior is worse:

    When a window starts is in a continued line, it is recentered whenever
    the window is unselected--by activating the minibuffer, switching to
    another window, or switching to another frame.

That is the spurious scrolling bug I have mentioned.  Thank you
for connecting it with specific code.  Now it should be possible
to track it down.

Yidong wrote:

    I don't know an easy way to fix this.

Can you describe the series of events that cause the
spurious recentering?