[gimp] app: gimp_session_info_dockable_restore(): don't return existing singletons

[Michael Natterer <mitch src gnome org>]

commit 80cf95319e559e9d601ac6cc494bea14faf477f5
Author: Michael Natterer <mitch gimp org>
Date:   Thu May 12 20:24:32 2011 +0200

    app: gimp_session_info_dockable_restore(): don't return existing singletons
    
    Instead, return NULL. The singleton dockable can't be restored in this
    dock because it's already open in another dock.

 app/widgets/gimpsessioninfo-dockable.c |    7 +++++++
 1 files changed, 7 insertions(+), 0 deletions(-)
---
diff --git a/app/widgets/gimpsessioninfo-dockable.c b/app/widgets/gimpsessioninfo-dockable.c
index 83ecff0..2604466 100644
--- a/app/widgets/gimpsessioninfo-dockable.c
+++ b/app/widgets/gimpsessioninfo-dockable.c
@@ -290,6 +290,13 @@ gimp_session_info_dockable_restore (GimpSessionInfoDockable *info,
 
   if (dockable)
     {
+      /*  gimp_dialog_factory_dockable_new() might return an already
+       *  existing singleton dockable, return NULL so our caller won't
+       *  try to add it to another dockbook
+       */
+      if (gimp_dockable_get_dockbook (GIMP_DOCKABLE (dockable)))
+        return NULL;
+
       gimp_dockable_set_locked    (GIMP_DOCKABLE (dockable), info->locked);
       gimp_dockable_set_tab_style (GIMP_DOCKABLE (dockable), info->tab_style);