diff --git a/src/compositor/meta-window-actor.c b/src/compositor/meta-window-actor.c
index 8c1617dea..ce691ae90 100644
--- a/src/compositor/meta-window-actor.c
+++ b/src/compositor/meta-window-actor.c
@@ -70,6 +70,9 @@ struct _MetaWindowActorPrivate
 
   /* A region that matches the shape of the window, including frame bounds */
   cairo_region_t   *shape_region;
+  /* The opaque region, from _NET_WM_OPAQUE_REGION, intersected with
+   * the shape region. */
+  cairo_region_t   *opaque_region;
   /* The region we should clip to when painting the shadow */
   cairo_region_t   *shadow_clip;
 
@@ -387,6 +390,7 @@ meta_window_actor_dispose (GObject *object)
   meta_window_actor_detach (self);
 
   g_clear_pointer (&priv->shape_region, cairo_region_destroy);
+  g_clear_pointer (&priv->opaque_region, cairo_region_destroy);
   g_clear_pointer (&priv->shadow_clip, cairo_region_destroy);
 
   g_clear_pointer (&priv->shadow_class, g_free);
@@ -1551,8 +1555,8 @@ meta_window_actor_get_obscured_region (MetaWindowActor *self)
 {
   MetaWindowActorPrivate *priv = self->priv;
 
-  if (!priv->argb32 && priv->opacity == 0xff && priv->back_pixmap)
-    return priv->shape_region;
+  if (priv->back_pixmap && priv->opacity == 0xff)
+    return priv->opaque_region;
   else
     return NULL;
 }
@@ -2182,6 +2186,27 @@ check_needs_reshape (MetaWindowActor *self)
   /* The region at this point should be constrained to the
    * bounds of the client rectangle. */
 
+  if (priv->argb32 && priv->window->opaque_region != NULL)
+    {
+      /* The opaque region is defined to be a part of the
+       * window which ARGB32 will always paint with opaque
+       * pixels. For these regions, we want to avoid painting
+       * windows and shadows beneath them.
+       *
+       * If the client gives bad coordinates where it does not
+       * fully paint, the behavior is defined by the specification
+       * to be undefined, and considered a client bug. In mutter's
+       * case, graphical glitches will occur.
+       */
+      priv->opaque_region = cairo_region_copy (priv->window->opaque_region);
+      cairo_region_translate (priv->opaque_region, client_area.x, client_area.y);
+      cairo_region_intersect (priv->opaque_region, region);
+    }
+  else if (priv->argb32)
+    priv->opaque_region = NULL;
+  else
+    priv->opaque_region = cairo_region_reference (region);
+
   if (needs_mask)
     {
       /* This takes the region, generates a mask using GTK+
diff --git a/src/core/window-private.h b/src/core/window-private.h
index becfef5d6..f7228ed2b 100644
--- a/src/core/window-private.h
+++ b/src/core/window-private.h
@@ -346,6 +346,9 @@ struct _MetaWindow
   /* if non-NULL, the bounds of the window frame */
   cairo_region_t *frame_bounds;
 
+  /* if non-NULL, the opaque region _NET_WM_OPAQUE_REGION */
+  cairo_region_t *opaque_region;
+
   /* Note: can be NULL */
   GSList *struts;
 
@@ -648,6 +651,7 @@ void meta_window_update_icon_now (MetaWindow *window);
 
 void meta_window_update_role (MetaWindow *window);
 void meta_window_update_net_wm_type (MetaWindow *window);
+void meta_window_update_opaque_region (MetaWindow *window);
 void meta_window_update_for_monitors_changed (MetaWindow *window);
 void meta_window_update_on_all_workspaces (MetaWindow *window);
 
diff --git a/src/core/window-props.c b/src/core/window-props.c
index e01934bcf..64bbdb28e 100644
--- a/src/core/window-props.c
+++ b/src/core/window-props.c
@@ -520,6 +520,14 @@ reload_wm_name (MetaWindow    *window,
     }
 }
 
+static void
+reload_opaque_region (MetaWindow    *window,
+                      MetaPropValue *value,
+                      gboolean       initial)
+{
+  meta_window_update_opaque_region (window);
+}
+
 static void
 reload_mutter_hints (MetaWindow    *window,
                      MetaPropValue *value,
@@ -1706,6 +1714,7 @@ meta_display_init_window_prop_hooks (MetaDisplay *display)
     { display->atom__NET_WM_PID,       META_PROP_VALUE_CARDINAL, reload_net_wm_pid,        TRUE,  TRUE },
     { XA_WM_NAME,                      META_PROP_VALUE_TEXT_PROPERTY, reload_wm_name,      TRUE,  TRUE },
     { display->atom__MUTTER_HINTS,     META_PROP_VALUE_TEXT_PROPERTY, reload_mutter_hints, TRUE,  TRUE },
+    { display->atom__NET_WM_OPAQUE_REGION, META_PROP_VALUE_CARDINAL_LIST, reload_opaque_region, TRUE, TRUE },
     { display->atom__NET_WM_ICON_NAME, META_PROP_VALUE_UTF8,     reload_net_wm_icon_name,  TRUE,  FALSE },
     { XA_WM_ICON_NAME,                 META_PROP_VALUE_TEXT_PROPERTY, reload_wm_icon_name, TRUE,  FALSE },
     { display->atom__NET_WM_DESKTOP,   META_PROP_VALUE_CARDINAL, reload_net_wm_desktop,    TRUE,  FALSE },
diff --git a/src/core/window.c b/src/core/window.c
index e5023e4a4..ead4d810f 100644
--- a/src/core/window.c
+++ b/src/core/window.c
@@ -226,6 +226,9 @@ meta_window_finalize (GObject *object)
   if (window->frame_bounds)
     cairo_region_destroy (window->frame_bounds);
 
+  if (window->opaque_region)
+    cairo_region_destroy (window->opaque_region);
+
   meta_icon_cache_free (&window->icon_cache);
 
   g_free (window->sm_client_id);
@@ -7388,6 +7391,64 @@ meta_window_update_net_wm_type (MetaWindow *window)
   meta_window_recalc_window_type (window);
 }
 
+void
+meta_window_update_opaque_region (MetaWindow *window)
+{
+  cairo_region_t *opaque_region = NULL;
+  gulong *region = NULL;
+  int nitems;
+
+  g_clear_pointer (&window->opaque_region, cairo_region_destroy);
+
+  if (meta_prop_get_cardinal_list (window->display,
+                                   window->xwindow,
+                                   window->display->atom__NET_WM_OPAQUE_REGION,
+                                   &region, &nitems))
+    {
+      cairo_rectangle_int_t *rects;
+      int i, rect_index, nrects;
+
+      if (nitems % 4 != 0)
+        {
+          meta_verbose ("_NET_WM_OPAQUE_REGION does not have a list of 4-tuples.");
+          goto out;
+        }
+
+      /* empty region */
+      if (nitems == 0)
+        goto out;
+
+      nrects = nitems / 4;
+
+      rects = g_new (cairo_rectangle_int_t, nrects);
+
+      rect_index = 0;
+      i = 0;
+      while (i < nitems)
+        {
+          cairo_rectangle_int_t *rect = &rects[rect_index];
+
+          rect->x = region[i++];
+          rect->y = region[i++];
+          rect->width = region[i++];
+          rect->height = region[i++];
+
+          rect_index++;
+        }
+
+      opaque_region = cairo_region_create_rectangles (rects, nrects);
+
+      g_free (rects);
+    }
+
+ out:
+  window->opaque_region = opaque_region;
+  meta_XFree (region);
+
+  if (window->display->compositor)
+    meta_compositor_window_shape_changed (window->display->compositor, window);
+}
+
 static void
 redraw_icon (MetaWindow *window)
 {
diff --git a/src/meta/atomnames.h b/src/meta/atomnames.h
index a8598e653..ca0520fd0 100644
--- a/src/meta/atomnames.h
+++ b/src/meta/atomnames.h
@@ -173,6 +173,7 @@ item(_NET_WM_STATE_STICKY)
 item(_NET_WM_FULLSCREEN_MONITORS)
 item(_NET_WM_STATE_FOCUSED)
 item(_NET_WM_BYPASS_COMPOSITOR)
+item(_NET_WM_OPAQUE_REGION)
 
 #if 0
 /* We apparently never use: */