GTK application menus are not correctly displayed

[Aurélien Gâteau]

When a GTK app is started, its menu appears in the menubar but clicking on any item will always show the menu for the first item. The menubar then clears itself until the application is restarted.

[Aurélien Gâteau (agateau)]

It seems GetLayout() implementation in dbusmenu-glib is buggy: it ignores the parentId parameter.

Getting first level of items for gedit:

# dbus-send --print-reply --dest=:1.442 /com/canonical/menu/7C000A3 com.canonical.dbusmenu.GetLayout int32:0 int32:1 'array:string:'

method return sender=:1.442 -> dest=:1.455 reply_serial=2
   uint32 2
   struct {
      int32 0
      array [
         dict entry(
            string "children-display"
            variant string "submenu"
         )
      ]
      array [
         variant struct {
               int32 2
               array [
                  dict entry(
                     string "children-display"
                     variant string "submenu"
                  )
                  dict entry(
                     string "label"
                     variant string "File"
                  )
               ]
               array [
               ]
            }
         variant struct {
               int32 3
               array [
                  dict entry(
                     string "children-display"
                     variant string "submenu"
                  )
                  dict entry(
                     string "label"
                     variant string "Edit"
                  )
               ]
               array [
               ]
            }
         variant struct {
               int32 4
               array [
                  dict entry(
                     string "children-display"
                     variant string "submenu"
                  )
                  dict entry(
                     string "label"
                     variant string "View"
                  )
               ]
               array [
               ]
            }
         variant struct {
               int32 5
               array [
                  dict entry(
                     string "children-display"
                     variant string "submenu"
                  )
                  dict entry(
                     string "label"
                     variant string "Search"
                  )
               ]
               array [
               ]
            }
         variant struct {
               int32 6
               array [
                  dict entry(
                     string "children-display"
                     variant string "submenu"
                  )
                  dict entry(
                     string "label"
                     variant string "Tools"
                  )
               ]
               array [
               ]
            }
         variant struct {
               int32 7
               array [
                  dict entry(
                     string "enabled"
                     variant boolean true
                  )
                  dict entry(
                     strin...