[gimp] app: fix update of group layers when size changes only trigger an offset change

[Michael Natterer <mitch src gnome org>]

commit 2f8476bd18ce2b01516133564e894be1d3c4b4c5
Author: Michael Natterer <mitch gimp org>
Date:   Tue Jun 23 10:24:25 2015 +0200

    app: fix update of group layers when size changes only trigger an offset change
    
    In gimp_group_layer_update_size(), when the new size happens to be the
    same as the old size, we need to call gimp_pickable_flush() on the
    group projection so it is ready to be used for rendering the image,
    just like in gimp_group_layer_stack_update().

 app/core/gimpgrouplayer.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/app/core/gimpgrouplayer.c b/app/core/gimpgrouplayer.c
index a6fa5e8..d562222 100644
--- a/app/core/gimpgrouplayer.c
+++ b/app/core/gimpgrouplayer.c
@@ -1208,6 +1208,9 @@ gimp_group_layer_update_size (GimpGroupLayer *group)
            */
           gimp_projectable_invalidate (GIMP_PROJECTABLE (group),
                                        x, y, width, height);
+
+          /*  see comment in gimp_group_layer_stack_update() below  */
+          gimp_pickable_flush (GIMP_PICKABLE (GET_PRIVATE (group)->projection));
         }
     }
 }