Placing on desktops (was: Theme patriation)

[Thomas Thurman <tthurman gnome org>]

Christoph and Allin raise the question of the placement of an 
application's windows on the same desktop every time the application 
starts.  This is known as "window matching", and there is currently no 
good way to do it.  The subject turns out to be on-topic for this list.

What people want is for "the same" window to appear in the same place.  
There is no clear answer to what "the same" means.  Obviously it's not 
really the same window, because the application closed in between and 
perhaps it's not even the same X session.  So we need to use some 
attribute of the window to decide whether it's "the same".

The ICCCM does provide a property called WM_CLASS which is supposed to 
be used for this (see 4.1.2.5).  Many applications don't set it and 
those which do don't set it consistently enough for it to be used in 
this way reliably. This is why Devil's Pie and gdevilspie require you to 
tweak WM_CLASS matching rules by hand. (There's also the matter of 
separation of concerns; Devil's Pie does work which a separate process 
can do for those who want it, so it seems less sensible to keep it in 
the window manager.)

The trouble is that knowing the semantics of a given window is not 
something the WM is best equipped to do.  The app is the only one 
which knows what its windows are for, and which of them should be 
restored to which positions, and I feel this is a job which would most 
appropriately be given to the toolkit.

peace

Thomas

-- 
Thomas Thurman, tthurman at gnome, http://blogs.gnome.org/tthurman
The only thing you might successfully put in the lamp is a fresh pair of batteries.