scrollbar (once more)

[Luc Teirlinck]

Just a strange little detail about the native scrollbar.  (I did not
check how other scrollbars behave in the same situation.)

Do C-h n, put the region around:

GNU Emacs NEWS -- history of user-visible changes.  2001-03-15
Copyright (C) 1999, 2000, 2001, 2002, 2003 Free Software Foundation,
Inc.  See the end for copying conditions.

Make sure that the trailing newline is included.

C-x n n.

The thumb now covers the entire scrollbar.  No problem with me.

Let us start with everybody's favorite activity: overscrolling.

Put the second line at the top, say with M-0 C-l, or by dragging the
scrollbar.  The thumb now occupies a little bit more than half of the
scrollbar, because that is the percentage of accessible characters
still visible.  Wonderful.

Third line to the top.  Thumb shrinks to expected size.

Final step of overscrolling: last line to the top.

The thumb now covers nearly the entire length of the scrollbar,
because the inaccessible portion all of a sudden starts "counting".

Does this make sense?

You can see a similar effect by doing C-h i m cl and overscrolling all
the way to the bottom.  Actually, this is the way I noticed the
problem, assuming it is one.  (In Info, it is confusing.)

I am afraid that I am starting to suffer from Obsessive Scrolling Disorder.

Sincerely,

Luc.