GdkEventClient? How can I get client messages from X?

[Andrew Shafer <shafer realmsys com>]

Is there an event mask or something that needs to be set to get client
messages from the X server?

I'm trying to get client messages from X with the Atom
_NET_STARTUP_INFO.

I tried registering a filter with gdk_add_client_message_filter:

gdk_add_client_message_filter(gdk_atom_intern("_NET_STARTUP_INFO",FALSE),
                                             my_filter_func,
                                             NULL);

I can see the filter get added to the display, and I can see the message
broadcast using xmon or the libstartup-notification
test-watch-xmessages, but I never get into the callback.

Any direction or insight would be greatly appreciated. . .

Regards