Window Manager and multiple application windows

Peter Harris peter.harris at
Tue Dec 16 12:30:49 PST 2008

Bipin George Mathew wrote:
> I actually did read about the the WM_HINTS window group in the ICCCM.

In my experience, TRANSIENT_FOR is used far more often than

> To
> be more specific with my question, it is not compulsory for a client who
> creates multiple top-level windows to specify the window group hint - In
> that case I guess there is no way for the window manager to find out the
> top-level windows that "belong" to an application. Am I right?

True, it is not mandatory. A single process can create multiple
"application" windows. The window manager should treat these as separate
applications. If a process wants a group of windows to "belong" to each
other, it will set TRANSIENT_FOR (or WM_HINTS->window_group).

You can look at the resource mask if you really need to know, but that
would break ICCCM.

Speaking of specs, you probably also want to support _MOTIF_WM_HINTS. It
isn't an official X standard, but many apps use it to declare the
decorations they want.

Peter Harris
               Open Text Connectivity Solutions Group
Peter Harris          
Research and Development        Phone: +1 905 762 6001
peter.harris at       Toll Free: 1 877 359 4866

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