notebook: Make dnd safe against tab disappearance

when the dragged tab is being removed during the drag operation,
we need to cancel the drag. To do so, we have to keep around
a reference to the drag context.

This should fix
https://bugzilla.gnome.org/show_bug.cgi?id=732051

diff --git a/gtk/gtknotebook.c b/gtk/gtknotebook.c
index 2bf9e74a65817d9ecd2e73dd37c93cfb9549e3af..aba3daa12346627b91e6b00e1c2b0da61469d8c5 100644 (file)
--- a/gtk/gtknotebook.c
+++ b/gtk/gtknotebook.c
@@ -3711,6 +3711,7 @@ gtk_notebook_drag_begin (GtkWidget        *widget,
                     G_CALLBACK (on_drag_icon_draw), notebook);
 
   gtk_drag_set_icon_widget (context, priv->dnd_window, -2, -2);
+  g_object_set_data (G_OBJECT (priv->dnd_window), "drag-context", context);
 }
 
 static void
@@ -5052,7 +5053,17 @@ gtk_notebook_real_remove (GtkNotebook *notebook,
     }
 
   if (priv->detached_tab == list->data)
-    priv->detached_tab = NULL;
+    {
+      priv->detached_tab = NULL;
+
+      if (priv->operation == DRAG_OPERATION_DETACH)
+        {
+          GdkDragContext *context;
+
+          context = (GdkDragContext *)g_object_get_data (G_OBJECT (priv->dnd_window), "drag-context");
+          gtk_drag_cancel (context);
+        }
+    }
   if (priv->prelight_tab == list->data)
     update_prelight_tab (notebook, NULL);
   if (priv->switch_tab == list)