diff --git a/gtk/a11y/gtkatspicontext.c b/gtk/a11y/gtkatspicontext.c
index a2d7b1079a..79d8e0b797 100644
--- a/gtk/a11y/gtkatspicontext.c
+++ b/gtk/a11y/gtkatspicontext.c
@@ -644,6 +644,7 @@ gtk_at_spi_context_state_change (GtkATContext                *ctx,
                                  GtkAccessibleStateChange     changed_states,
                                  GtkAccessiblePropertyChange  changed_properties,
                                  GtkAccessibleRelationChange  changed_relations,
+                                 GtkAccessiblePlatformChange  changed_platform,
                                  GtkAccessibleAttributeSet   *states,
                                  GtkAccessibleAttributeSet   *properties,
                                  GtkAccessibleAttributeSet   *relations)
diff --git a/gtk/gtkaccessible.c b/gtk/gtkaccessible.c
index 2b828b2254..dd5890ca92 100644
--- a/gtk/gtkaccessible.c
+++ b/gtk/gtkaccessible.c
@@ -636,3 +636,16 @@ gtk_accessible_role_to_name (GtkAccessibleRole  role,
 
   return role_names[role];
 }
+
+void
+gtk_accessible_platform_changed (GtkAccessible               *self,
+                                 GtkAccessiblePlatformChange  change)
+{
+  GtkATContext *context = gtk_accessible_get_at_context (self);
+  if (context == NULL)
+    return;
+
+  gtk_at_context_platform_changed (context, change);
+  gtk_at_context_update (context);
+}
+
diff --git a/gtk/gtkaccessibleattributesetprivate.h b/gtk/gtkaccessibleattributesetprivate.h
index 83694c7ede..bce94d6876 100644
--- a/gtk/gtkaccessibleattributesetprivate.h
+++ b/gtk/gtkaccessibleattributesetprivate.h
@@ -20,7 +20,7 @@
 
 #pragma once
 
-#include "gtkaccessibleprivate.h"
+#include "gtkaccessible.h"
 #include "gtkaccessiblevalueprivate.h"
 
 G_BEGIN_DECLS
diff --git a/gtk/gtkaccessibleprivate.h b/gtk/gtkaccessibleprivate.h
index a118f6c150..05351d4526 100644
--- a/gtk/gtkaccessibleprivate.h
+++ b/gtk/gtkaccessibleprivate.h
@@ -21,7 +21,7 @@
 #pragma once
 
 #include "gtkaccessible.h"
-#include "gtkatcontext.h"
+#include "gtkatcontextprivate.h"
 
 G_BEGIN_DECLS
 
@@ -37,4 +37,7 @@ GtkATContext *  gtk_accessible_get_at_context   (GtkAccessible *self);
 const char *    gtk_accessible_role_to_name     (GtkAccessibleRole  role,
                                                  const char        *domain);
 
+void gtk_accessible_platform_changed (GtkAccessible               *self,
+                                      GtkAccessiblePlatformChange  change);
+
 G_END_DECLS
diff --git a/gtk/gtkatcontext.c b/gtk/gtkatcontext.c
index 085bf989b2..121951ab9d 100644
--- a/gtk/gtkatcontext.c
+++ b/gtk/gtkatcontext.c
@@ -36,6 +36,7 @@
 #include "gtkatcontextprivate.h"
 
 #include "gtkaccessiblevalueprivate.h"
+#include "gtkaccessibleprivate.h"
 #include "gtkdebug.h"
 #include "gtktestatcontextprivate.h"
 #include "gtktypebuiltins.h"
@@ -137,6 +138,7 @@ gtk_at_context_real_state_change (GtkATContext                *self,
                                   GtkAccessibleStateChange     changed_states,
                                   GtkAccessiblePropertyChange  changed_properties,
                                   GtkAccessibleRelationChange  changed_relations,
+                                  GtkAccessiblePlatformChange  changed_platform,
                                   GtkAccessibleAttributeSet   *states,
                                   GtkAccessibleAttributeSet   *properties,
                                   GtkAccessibleAttributeSet   *relations)
@@ -505,7 +507,8 @@ gtk_at_context_update (GtkATContext *self)
   /* There's no point in notifying of state changes if there weren't any */
   if (self->updated_properties == 0 &&
       self->updated_relations == 0 &&
-      self->updated_states == 0)
+      self->updated_states == 0 &&
+      self->updated_platform == 0)
     return;
 
   GtkAccessibleStateChange changed_states =
@@ -517,12 +520,14 @@ gtk_at_context_update (GtkATContext *self)
 
   GTK_AT_CONTEXT_GET_CLASS (self)->state_change (self,
                                                  changed_states, changed_properties, changed_relations,
+                                                 self->updated_platform,
                                                  self->states, self->properties, self->relations);
   g_signal_emit (self, obj_signals[STATE_CHANGE], 0);
 
   self->updated_properties = 0;
   self->updated_relations = 0;
   self->updated_states = 0;
+  self->updated_platform = 0;
 }
 
 /*< private >
@@ -806,3 +811,10 @@ gtk_at_context_get_label (GtkATContext *self)
 
   return g_strdup ("widget");
 }
+
+void
+gtk_at_context_platform_changed (GtkATContext                *self,
+                                 GtkAccessiblePlatformChange  change)
+{
+  self->updated_platform |= change;
+}
diff --git a/gtk/gtkatcontextprivate.h b/gtk/gtkatcontextprivate.h
index 15da90acfe..fb396c8ccc 100644
--- a/gtk/gtkatcontextprivate.h
+++ b/gtk/gtkatcontextprivate.h
@@ -80,6 +80,11 @@ typedef enum {
   GTK_ACCESSIBLE_STATE_CHANGE_SELECTED = 1 << GTK_ACCESSIBLE_STATE_SELECTED
 } GtkAccessibleStateChange;
 
+typedef enum {
+  GTK_ACCESSIBLE_PLATFORM_CHANGE_FOCUSABLE = 1 << 0,
+  GTK_ACCESSIBLE_PLATFORM_CHANGE_FOCUSED   = 1 << 1,
+} GtkAccessiblePlatformChange;
+
 struct _GtkATContext
 {
   GObject parent_instance;
@@ -95,6 +100,7 @@ struct _GtkATContext
   GtkAccessibleStateChange updated_states;
   GtkAccessiblePropertyChange updated_properties;
   GtkAccessibleRelationChange updated_relations;
+  GtkAccessiblePlatformChange updated_platform;
 };
 
 struct _GtkATContextClass
@@ -105,6 +111,7 @@ struct _GtkATContextClass
                          GtkAccessibleStateChange     changed_states,
                          GtkAccessiblePropertyChange  changed_properties,
                          GtkAccessibleRelationChange  changed_relations,
+                         GtkAccessiblePlatformChange  changed_platform,
                          GtkAccessibleAttributeSet   *states,
                          GtkAccessibleAttributeSet   *properties,
                          GtkAccessibleAttributeSet   *relations);
@@ -138,6 +145,9 @@ GtkAccessibleValue *    gtk_at_context_get_accessible_relation  (GtkATContext
 
 char *                  gtk_at_context_get_label                (GtkATContext          *self);
 
+void                    gtk_at_context_platform_changed         (GtkATContext                *self,
+                                                                 GtkAccessiblePlatformChange  change);
+
 const char *    gtk_accessible_property_get_attribute_name      (GtkAccessibleProperty property);
 const char *    gtk_accessible_relation_get_attribute_name      (GtkAccessibleRelation relation);
 const char *    gtk_accessible_state_get_attribute_name         (GtkAccessibleState    state);
diff --git a/gtk/gtktestatcontext.c b/gtk/gtktestatcontext.c
index e1bf0f5d1d..6358c196ce 100644
--- a/gtk/gtktestatcontext.c
+++ b/gtk/gtktestatcontext.c
@@ -23,6 +23,7 @@
 #include "gtktestatcontextprivate.h"
 
 #include "gtkatcontextprivate.h"
+#include "gtkaccessibleprivate.h"
 #include "gtkdebug.h"
 #include "gtkenums.h"
 #include "gtkprivate.h"
@@ -45,6 +46,7 @@ gtk_test_at_context_state_change (GtkATContext                *self,
                                   GtkAccessibleStateChange     changed_states,
                                   GtkAccessiblePropertyChange  changed_properties,
                                   GtkAccessibleRelationChange  changed_relations,
+                                  GtkAccessiblePlatformChange  changed_platform,
                                   GtkAccessibleAttributeSet   *states,
                                   GtkAccessibleAttributeSet   *properties,
                                   GtkAccessibleAttributeSet   *relations)