Re: Weirdness with Emacs' X window id

["Jan D." <jan.h.d@swipnet.se>]

Peter Heslin wrote:

>In Debian GNU/Linux:
>
>If I do emacs -q --no-site-file with a month-old CVS checkout, and
>then M-x eshell:
>
>~ $ xdpyinfo |grep -i focus
>focus:  window 0x1400015, revert to Parent
>~ $ wmctrl -l |grep -i emacs
>0x01400014 1 aideen Emacs *eshell*
>
>where wmctrl is a command-line program and the -l switch makes it list
>all current windows.  Note that xdpyinfo and wmctrl disagree as to
>what should be the ID number for the single Emacs frame.  One says a
>number ending in 14, the other in 15.
>
>wmctrl -l does not know of any window with the ID 0x1400015.
>
>Is this expected?  I don't know anything about these IDs -- I'm just
>trying to write a script to manipulate windows on my desktop, and
>it's quite difficult with this ID schizophrenia.
>
>Emacs is the only application I run that behaves like this.
>
>If it's not expected behavior, then it could be a bug in wmctrl,
>xdpyinfo, my X server, Emacs, or who knows where, so it would be
>interesting to see if anyone else sees this.
>

It is normal.  The window manager may set windows between the Emacs 
window and the root window.  Also, there is a special window called the 
client leader window used for session handling.  I don't know which 
window wmctrl  returns, it can be any of these.  To see all windows 
Emacs has, use:

% xwininfo -tree -id 0x1400015

(or 14).

    Jan D.