static void
X11GD_SetFullscreenMode(Window win, jboolean enabled)
{
    Atom wmState = XInternAtom(awt_display, "_NET_WM_STATE", False);
    Atom wmStateFs = XInternAtom(awt_display,
                                 "_NET_WM_STATE_FULLSCREEN", False);
    Window root, parent, *children = NULL;
    unsigned int numchildren;
    XEvent event;
    Status status;

    if (wmState == None || wmStateFs == None) {
        return;
    }

    /*
     * Note: the Window passed to this method is typically the "content
     * window" of the top-level, but we need the actual shell window for
     * the purposes of constructing the XEvent.  Therefore, we walk up the
     * window hierarchy here to find the true top-level.
     */
    do {
        if (!XQueryTree(awt_display, win,
                        &root, &parent,
                        &children, &numchildren))
        {
            return;
        }

        if (children != NULL) {
            XFree(children);
        }

        if (parent == root) {
            break;
        }

        win = parent;
    } while (root != parent);

    memset(&event, 0, sizeof(event));
    event.xclient.type = ClientMessage;
    event.xclient.message_type = wmState;
    event.xclient.display = awt_display;
    event.xclient.window = win;
    event.xclient.format = 32;
    event.xclient.data.l[0] = enabled ? 1 : 0; // 1==add, 0==remove
    event.xclient.data.l[1] = wmStateFs;

    XSendEvent(awt_display, root, False,
               SubstructureRedirectMask | SubstructureNotifyMask,
               &event);
    XSync(awt_display, False);
}

Atom wmStateAbove = XInternAtom(awt_display, "_NET_WM_STATE_ABOVE", False);
event.xclient.data.l[2] = wmStateAbove;
Atom types[2]={0};
int ntypes=0;
types[ntypes++] = wmStateFs;
types[ntypes++] = wmStateAbove;
XChangeProperty( awt_display, win, wmState, XA_ATOM, 32, PropModeReplace, (unsigned char *)&types, ntypes);