Comment 8 for bug 1667227

gtk_main_get_window_group function return different results for gtk_grab_add and gtk_grab_remove, but widget address was same in both functions:

  if (GTK_IS_WINDOW (toplevel))
    return gtk_window_get_group (GTK_WINDOW (toplevel));
  else
    return gtk_window_get_group (NULL);

On gtk_grab_add window group is 0x555555b0b160 for widget 0x555555e50780:
Thread 1 "mate-terminal" hit Breakpoint 3, gtk_main_get_window_group (widget=0x555555e50780) at ././gtk/gtkmain.c:2
025
2025 if (GTK_IS_WINDOW (toplevel))
$2044 (widget) = 0x555555e50780
$2045 (toplevel) = 0x555555e50780
$2046 (*widget) = {parent_instance = {g_type_instance = {g_class = 0x555555e5e800}, ref_count = 1, qdata = 0x2}, priv = 0x555
555e50690}
$2047 (*widget.priv) = {..., window = 0x0, registered_windows = 0x0, parent = 0x0, event_contr
ollers = 0x0, accessible = 0x0}
#0 gtk_main_get_window_group (widget=0x555555e50780) at ././gtk/gtkmain.c:2025
#1 0x00007ffff71f3bb3 in gtk_grab_add (widget=0x555555e50780) at ././gtk/gtkmain.c:2231
#2 0x00007ffff70ac1d1 in gtk_cell_renderer_accel_start_editing (cell=0x555555845270, event=0x555555d416f0, widget=
0x555555e183f0, path=0x555555e57720 "2:0", background_area=0x7fffffffc2e0, cell_area=0x7fffffffc2e0, flags=(unknown
: 0)) at ././gtk/gtkcellrendereraccel.c:497
#3 0x00007ffff70a92dd in gtk_cell_renderer_start_editing (cell=0x555555845270, event=0x555555d416f0, widget=0x5555
55e183f0, path=0x555555e57720 "2:0", background_area=0x7fffffffc2e0, cell_area=0x7fffffffc2e0, flags=(unknown: 0))
at ././gtk/gtkcellrenderer.c:921
#4 0x00007ffff709d47e in gtk_cell_area_activate_cell (area=0x555555e0d140, widget=0x555555e183f0, renderer=0x555555845270, event=0x555555d416f0, cell_area=0x7fffffffc380, flags=(unknown: 0)) at ././gtk/gtkcellarea.c:3432
#5 0x00007ffff7096407 in gtk_cell_area_real_event (area=0x555555e0d140, context=0x555555e26850, widget=0x555555e183f0, event=0x555555d416f0, cell_area=0x7fffffffc570, flags=(unknown: 0)) at ././gtk/gtkcellarea.c:1101

At time of gtk_grab_remove, when event is delivered to widget 0x555555e50780 from gtk_main_do_event, its toplevel was 0x555555ddb0d0
Thread 1 "mate-terminal" hit Breakpoint 3, gtk_main_get_window_group (widget=0x555555e50780) at ././gtk/gtkmain.c:2025
2025 if (GTK_IS_WINDOW (toplevel))
$2092 (widget) = 0x555555e50780
$2093 (toplevel) = 0x555555ddb0d0
$2094 (*widget) = {parent_instance = {g_type_instance = {g_class = 0x555555e5e800}, ref_count = 7, qdata = 0x555555ecf180}, priv = 0x555555e50690}
$2095 (*widget.priv) = {...., window = 0x555555e507e0, registered_windows = 0x55555595
7d00, parent = 0x555555e183f0, event_controllers = 0x0, accessible = 0x555555e1d320}
#0 gtk_main_get_window_group (widget=0x555555e50780) at ././gtk/gtkmain.c:2025
#1 0x00007ffff71f3d8c in gtk_grab_remove (widget=0x555555e50780) at ././gtk/gtkmain.c:2286
#2 0x00007ffff70ac56b in gtk_cell_editable_event_box_key_press_event (widget=0x555555e50780, event=0x555555e473c0)
 at ././gtk/gtkcellrendereraccel.c:645

Parent of the widget was changed by gtk_tree_view_multipress_gesture_pressed -> .. -> gtk_cell_area_activate_cell -> gtk_cell_area_add_editable -> ..signal.. -> gtk_tree_view_column_add_editable_callback -> _gtk_tree_view_add_editable -> gtk_tree_view_put -> gtk_widget_set_parent

So, gtk_cell_area_activate_cell of gtk+3 (3.22.7) has incorrect order of actions which broke gtk_grab_add / gtk_grab_remove pair
https://github.com/GNOME/gtk/blob/6cc08d60efeb02afc0d67982c3dc205dfd16d7cd/gtk/gtkcellarea.c#L3388

3428 gtk_cell_renderer_start_editing (renderer,
...
3444 gtk_cell_area_add_editable (area, priv->focus_cell, editable_widget, cell_area);