bug#3454: <SPC> when reading the emacs manual sometimes goes to the wrong node

<SPC> when reading the emacs manual sometimes goes to the wrong node.

Emacs version: GNU Emacs 23.0.94.1 (i686-pc-linux-gnu, GTK+ Version 2.10.4)
 of 2009-05-26 (built from pretest source tarball)

Running on CentOS 5.3.
No options given to configure.
Also tested on Windows with same results.


How to reproduce:

Run emacs -Q
C-h r (Reads emacs manual)
g Command Index (takes you to the "Command and Function Index" page of the
manual)
M-> (Go to end of info node)

At this point, your cursor should be at the end of the info node that lists
all commands and functions.  Note that at the top, the next node is listed
as "Variable Index".  I would expect that pressing <SPC> would take you to
this node.  However, if you press <SPC> it takes you to some other node.  It
takes me to the middle of the node "49 Two-Column Editing".

I believe <DEL> has a similar problem, but I didn't narrow down a test case.

According to the manual for Info, "You can read an entire manual top to
bottom by just typing <SPC>".  So it seemed strange to me that pressing
<SPC> went to some place in the middle of the manual instead of the next
node.

This problem also existed in emacs 22.3.