Re: Gtk scrollbar: thumb too short

[Luc Teirlinck]

Robert Chassell wrote:

   I prefer that the thumb show the visible accessible portion of the
   whole, that is to say, the part that is accessible either because it
   is visible or because it is not hidden by narrowing.

   This means that if you make some text invisible, for example by type
   `C-c C-t' (hide-body) in outline mode, the thumb grows larger.

   Likewise, if you make some text invisible and inaccessible by
   narrowing to a smaller region, the thumb grows larger.

   This is the way it is done in Emacs 20.7.

I believe that there may be some confusion here.  If you make stuff
invisible in such a way that the total amount of text (visible and
invisible), between the position at the top of the screen and the one
at the bottom of the screen, increases, the thumb size increases.  If
you are careful to only make stuff outside the screen invisible,
nothing happens to the thumb.  (Tested in Emacs 20.7, native
scrollbars.)  M-1 C-x $ is a good way to experiment, with text
deliberately indented for he purpose.

In other words, what the thumb seems to measure is the proportion of
total (visible or invisible) text between top and bottom of the screen
compared to the total text in the buffer. 

This seems to be the behavior in Emacs 20.7 with native scrollbars, as
well as in the current 21.3.50 CVS, both with native 
(./configure --without-toolkit-scroll-bars) and with Xaw3d (no options
to configure) scroll bars.

Sincerely,

Luc.