Re: [Maybe OT]: Sawfish 'strange' behaviours

[Havoc Pennington <hp redhat com>]

rob <mailingLists pangolin org uk> writes:  
> It's what every other app dose (and it's what you said to do in the GGAD
> book). 

Sure, but I was wrong. ;-) At least according to the ICCCM.

> Reading the ICCCM it seems to do what you'd expect: the class bit
> specifies some set of windows that should be considered a group and type
> is used to differentiate between windows of the same class.(btw i
> couldn't find where it said that class and type should be the same all I
> could find was section 4.2.1.5 on the WM_CLASS)

What 4.1.2.5 says is that the name should identify an application
instance, not a window type. It also specifies that you should use the
following algorithm to set the class name:

 - the -name command line arg
 - else RESOURCE_NAME env variable
 - else the trailing part of argv[0]

And the class should be a string that's the same across all
application instances that are the same type of application.

So GTK pretty much already does that stuff, except that it uses --name
instead of -name and I think ignores RESOURCE_NAME. Anyway, we
typically end up with argv[0].

> Setting the role seems to enable you to tell apart windows of the same
> type. But you'd still need to set the class bit unless your happy with
> what ever default one you get.

The role "uniquely identifies a window among all the windows that have
the same client leader window." So for "singleton" windows such as a
preferences dialog the role can reflect the type of window, and for
window types that can have multiple instances (e.g. a document window)
it would probably include some kind of unique ID. The primary purpose
of the role is for session management.
 
> The result of all this is that new windows are created the same size as
> the last window of the same type, they stack properly on the panel, and
> have the correct icon. 
> If I don't set the WM_CLASS all windows of the app are created the same
> size(which looks real ugly if the main window is maximised and you pop
> up a one line dialog which also maximises itself), and they don't stack
> properly on the panel. 
>
> Looking at the gtk2 docs it seems as if by default it sets the class to
> the name of the app and the type to the name of the window (which is
> probably what is wanted most of the time but wouldn't work for me as I
> have windows from different apps in the same class). But then it says
> that class and type are always set to the same thing so I don't know. 
>
> Ok I've probably bored and confused everybody by now so I'll stop

No, it's a legitimate issue. The problem is that what the ICCCM
specifies really isn't useful, so lots of window managers have this
"identify windows by class/role" feature that works best if apps do
something nonstandard. But not all window managers do that. 
And so it's just a totally unspecified mess and you can't do anything
that will really work reliably.

IMO the correct solution is to have the window manager ignore the
class/name for the most part.

Havoc