Re: line-spacing and (recenter -1)

[Richard Stallman]

    Well, in 21.3, emacs automatically turns on window-vscroll to make the
    last line visible, whereas CVS emacs doesn't do this, and consequently
    fails to move the cursor line to the bottom of the screen (it happens to
    be only partially visible, so CVS emacs will scroll by lines in this case).

    This is caused by the following change:

    2002-07-07  Richard M. Stallman  <address@hidden>

            * xdisp.c (make_cursor_line_fully_visible): Don't try short scrolls.
            Instead just return 0 when there is something to be done.
            (try_scrolling): If make_cursor_line_fully_visible returns 0,
            retry scrolling as if cursor were off the bottom.
            (try_cursor_movement): If make_cursor_line_fully_visible returns 0,
            return CURSOR_MOVEMENT_MUST_SCROLL.
            (redisplay_window): If make_cursor_line_fully_visible returns 0,
            go to try_to_scroll.

That change fixed many bugs in scrolling.  It means that the caller of
make_cursor_line_fully_visible is now responsible for doing whatever
is necessary to scroll properly.

If the change caused some new bug, it probably means some caller of
make_cursor_line_fully_visible is not doing the right thing when that
function returns 0.  If you can determine which caller it is, the bug
is probably not hard to fix.