23.0.50; display property, continuation arrows and fringes

[Stephen Berman]

GNU Emacs 23.0.50.1 (i686-pc-linux-gnu, GTK+ Version 2.12.0) of
2007-12-09 on escher

1. emacs -Q

2. When a line of text ends in the column just before the right fringe,
then placing the cursor after the last character in the line displays
it in the fringe, as usual.  

3. With auto-fill mode disabled, now typing SPC makes continuation
arrows appear in both fringes, as usual.

4. Now evaluate the following sexp: (put-text-property (1- (point))
(point) 'display "x\n").

5. Now the continuation arrows still appear, `x' appears after the
left continuation arrow, below the original line of text, and the
cursor appears below `x'.

6. Now typing C-b makes the cursor appear on top of `x', and typing
C-b again then makes the cursor appear on top of the last character of
the original line of text, just before the right continuation arrow.

7. Now typing C-f makes the cursor vanish.  Is this supposed to
happen?  (Typing C-f again makes the cursor appears below `x'.)

(When I do the above with my initializations and customizations, the
cursor also vanishes after the first C-b in step 6.  I haven't yet
tried to find out what causes this difference from the behavior with
-Q.)

Steve Berman