Unexpected recentering

[MIYOSHI Masanori]

In GNU Emacs 22.0.990 on Windows, when the cursor is moved up to
the taller line, it sometimes jumps back to the center of the
window.

The following operation reproduces the problem.

1. emacs -q
2. C-x C-f somewhere/attached.txt ;; Read the attached file.
3. M-x show-paren-mode
4. M-x highlight-regexp RET Larger RET hi-black-hb
   ;; Now the highlighted line is taller than others.
5. M-: (setq scroll-step 1)
6. M-: (setq scroll-margin 1)
7. M->
8. C-p ;; Move the cursor STEPWISE up to the highlighted line.  When the
       ;; cursor gets there, it jumps back to the center of the window.

(
Larger than the default line height
)
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--
MIYOSHI Masanori