Hi,
I want to create a window that doesn't to be included in the taskbar
with this code

// Open the display
Display *dpy = XOpenDisplay(NIL);
assert(dpy);

// Get some colors
int blackColor = BlackPixel(dpy, DefaultScreen(dpy));
int whiteColor = WhitePixel(dpy, DefaultScreen(dpy));

// Create the window
Window w = XCreateSimpleWindow(dpy, DefaultRootWindow(dpy), 0, 0,

200, 100, 0, blackColor, blackColor);
XMapWindow(dpy, w);
Atom skip_taskbar = XInternAtom(dpy, "_NET_WM_STATE_SKIP_TASKBAR",
False);
if(skip_taskbar != None)
{
XEvent event;
event.xclient.type = ClientMessage;
event.xclient.serial = 0;
event.xclient.send_event = True;
event.xclient.window = w;
event.xclient.message_type = XInternAtom(dpy, "_NET_WM_STATE",
False);
event.xclient.format = 32;
event.xclient.data.l[0] = 1;
event.xclient.data.l[1] = skip_taskbar;
event.xclient.data.l[2] = skip_taskbar;

XSendEvent(dpy, DefaultRootWindow(dpy), False,
SubstructureRedirectMask | SubstructureNotifyMask, &event);
}

XFlush(dpy);
// Wait for 10 seconds
sleep(10);
}

but this code doesn't work on redhat 9/FC5
and xprop returns about the window, the _NET_WM_STATE_SKIP_TASKBAR is
not set.

I've tried many code from google...but all can't work..
what do i miss?

Thanks
Jinhao