23.0.60; format-time-string, post-command-hook and mark

[Stephen Berman]

1. Start Emacs with these arguments:
      -Q --eval "(add-hook 'post-command-hook (lambda () (format-time-string 
\"%Y\")))"

2. Load a file into a buffer or type some text in a buffer.

3. If you select a region of the buffer with the mouse and try to delete
the region with C-w, Emacs beeps and says "The mark is not active now"
and the region is not deleted.

4. Type C-SPC and see the message "Mark activated"; type C-SPC again and
see the message "Transient-mark-mode temporarily enabled".  However,
moving point does not show a highlighted expanding or contracting
region.

5. If you load an elisp file and select an uncommented region with the
mouse or by temporarily enabling transient-mark-mode, then typing M-;
does not comment out the region, but puts a comment string at the end of
the region.

Repeat the above with Emacs 23.0.50: doing C-w at step 3 deletes the
region, moving point in step 4 shows the highlighted region, typing M-;
in step 5 comments out the region.

I can reproduce the above observations for 23.0.60 with any nonempty
format string as argument to format-time-string, e.g. with "test" but
not with "" (with the latter 23.0.60 behaves like 23.0,50 with nonempty
format strings).  I cannot reproduce the observations for 23.0.60 if
format-time-string is not added to post-command-hook.

In GNU Emacs 23.0.60.2 (i686-pc-linux-gnu, GTK+ Version 2.12.0) of
2008-02-11 on escher

Steve Berman