Get GtkWindow focus from XI Event

[Takao Fujiwara <tfujiwar redhat com>]

I have a focus problem with the attached program.
1. When press Ctrl-Alt-v, my window is launched with the keyboard focus.
2. Click [x] button and close the window.
3. When press Ctrl-Alt-v again, my window is launched but the focus status is different by desktop.

XFCE4 desktop can get the keyboard focus correctly.
But GNOME, MATE or Plasma desktop cannot get the keyboard focus in the second Ctrl-Alt-v.

How should I investigate it?
The current workaround is to close the second window and launch the third window by the program but not XI 
shortcut key.

Thanks,
Fujiwara

---------
// gcc -o a a.c `pkg-config --cflags --libs gtk+-3.0 x11 xi`
#include <gtk/gtk.h>
#include <gdk/gdkx.h>
#include <X11/extensions/XInput2.h>
#include <string.h>

guint shortcut_keysym = 0;
guint shortcut_modifiers = 0;

static void
loop_quit (GtkWindow *window,
           gpointer   data)
{
    GMainLoop *loop = data;
    g_return_if_fail (loop != NULL);
    gtk_widget_hide (GTK_WIDGET (window));
    while (gtk_events_pending ()) {
        gtk_main_iteration ();
    }
    g_main_loop_quit (loop);
}

GtkWidget *
my_window_new (GMainLoop *loop) {
    GtkWidget *window=gtk_window_new (GTK_WINDOW_TOPLEVEL);
    gtk_window_set_default_size(GTK_WINDOW(window), 200, 200);
    gtk_window_set_position(GTK_WINDOW(window), GTK_WIN_POS_CENTER);
    g_signal_connect(window, "destroy", G_CALLBACK(loop_quit), loop);

    GtkWidget *entry = gtk_entry_new ();

    GtkWidget *grid=gtk_grid_new();
    gtk_grid_attach(GTK_GRID(grid), entry, 0, 0, 1, 1);

    gtk_container_add(GTK_CONTAINER(window), grid);

    return window;
}

static XIGrabModifiers *
get_grab_modifiers (guint  modifiers,
                    int   *result_length)
{
    XIGrabModifiers *ximodifiers = g_new0 (XIGrabModifiers, 1);
    XIGrabModifiers ximodifier = { 0, };
    memset (&ximodifier, 0, sizeof (XIGrabModifiers));
    ximodifier.modifiers = modifiers;
    ximodifier.status = 0;
    ximodifiers[0] = ximodifier;
    if (result_length)
        *result_length = 1;
    return ximodifiers;
}

static void
grab_keycode (guint keysym,
              guint modifiers)
{
    GdkDisplay *display = gdk_display_get_default ();
    Display *xdisplay = gdk_x11_display_get_xdisplay (display);
    guint keycode = 0;
    XIEventMask evmask = { 0, };
    int length = 0;
    XIGrabModifiers *ximodifiers;

    keycode = XKeysymToKeycode (xdisplay, keysym);
    memset (&evmask, 0, sizeof (XIEventMask));
    evmask.deviceid = XIAllMasterDevices;
    evmask.mask = g_new0 (guchar, (XI_LASTEVENT + 7) / 8);
    evmask.mask_len = (XI_LASTEVENT + 7) / 8;
    XISetMask (evmask.mask, XI_KeyPress);
    XISetMask (evmask.mask, XI_KeyRelease);
    ximodifiers = get_grab_modifiers (modifiers, &length);
    XIGrabKeycode (xdisplay,
                   XIAllMasterDevices,
                   keycode,
                   DefaultRootWindow (xdisplay),
                   GrabModeAsync,
                   GrabModeAsync,
                   TRUE,
                   &evmask,
                   length,
                   ximodifiers);
    g_free (ximodifiers);
}

static void
ungrab_keycode (guint keysym,
                guint modifiers)
{
    GdkDisplay *display = gdk_display_get_default ();
    Display *xdisplay = gdk_x11_display_get_xdisplay (display);
    guint keycode = 0;
    int length = 0;
    XIGrabModifiers *ximodifiers;

    keycode = XKeysymToKeycode (xdisplay, keysym);
    ximodifiers = get_grab_modifiers (modifiers, &length);
    XIUngrabKeycode (xdisplay,
                     XIAllMasterDevices,
                     keycode,
                     DefaultRootWindow (xdisplay),
                     length,
                     ximodifiers);
    g_free (ximodifiers);
}

static void
run_window ()
{
    GtkWidget *window;
    GMainLoop *loop;

    loop = g_main_loop_new (NULL, FALSE);
    window = my_window_new (loop);
    gtk_widget_show_all(window);

    g_main_loop_run (loop);
}

static void
event_handler (GdkEvent *event,
               gpointer  data)
{
    static int times = 0;
    if (((GdkEventAny*)event)->window == gdk_get_default_root_window() &&
         event->type == GDK_KEY_PRESS) {
        guint keyval = ((GdkEventKey*)event)->keyval;
        guint modifiers = ((GdkEventKey*)event)->state;
        if (keyval >= GDK_KEY_A && keyval <= GDK_KEY_Z &&
            (modifiers & GDK_SHIFT_MASK) != 0) {
            keyval = keyval - GDK_KEY_A + GDK_KEY_a;
        }
        if (keyval == shortcut_keysym &&
            modifiers == shortcut_modifiers) {
            run_window ();
            times++;
            if (times > 1) {
                ungrab_keycode (keyval, modifiers);
                gtk_main_quit();
            }
        }
    }
    gtk_main_do_event (event);
}

int
main (int argc, char *argv[])
{

    GtkWidget *window;
    GMainLoop *loop;
    gtk_init (&argc, &argv);

    gdk_event_handler_set (event_handler, NULL, NULL);

    gtk_accelerator_parse ("<Control><Alt>v",
                           &shortcut_keysym,
                           &shortcut_modifiers);
    grab_keycode (shortcut_keysym, shortcut_modifiers);

    gtk_main();
    return 0;
}