stack: Fix check if page is selected

When there is no visible child, gtk_selection_model_is_selected()
was returning TRUE for any invalid position.

So check if the page is non-NULL and match

diff --git a/gtk/gtkstack.c b/gtk/gtkstack.c
index 9b1488b3b20a261f275201bee5c1d4d05b2e2ced..e784b0c30f4fbd05f3312d653197de518166cbde 100644 (file)
--- a/gtk/gtkstack.c
+++ b/gtk/gtkstack.c
@@ -562,7 +562,7 @@ gtk_stack_pages_is_selected (GtkSelectionModel *model,
 
   page = g_list_nth_data (priv->children, position);
 
-  return page == priv->visible_child;
+  return page && page == priv->visible_child;
 }
 
 static void set_visible_child (GtkStack               *stack,