[gimp] app: don't call gimp_layer_set_lock_alpha() on layer groups

[Michael Natterer <mitch src gnome org>]

commit de5bbd637e8a8ab978d1e7783a6c62942533b7f3
Author: Michael Natterer <mitch gimp org>
Date:   Sat Sep 17 19:19:30 2016 +0200

    app: don't call gimp_layer_set_lock_alpha() on layer groups
    
    in gimp_image_new_from_drawable().

 app/core/gimpimage-new.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/app/core/gimpimage-new.c b/app/core/gimpimage-new.c
index eeafca8..13d114a 100644
--- a/app/core/gimpimage-new.c
+++ b/app/core/gimpimage-new.c
@@ -225,7 +225,8 @@ gimp_image_new_from_drawable (Gimp         *gimp,
   gimp_item_set_linked (GIMP_ITEM (new_layer), FALSE, FALSE);
   gimp_layer_set_mode (new_layer, GIMP_NORMAL_MODE, FALSE);
   gimp_layer_set_opacity (new_layer, GIMP_OPACITY_OPAQUE, FALSE);
-  gimp_layer_set_lock_alpha (new_layer, FALSE, FALSE);
+  if (gimp_layer_can_lock_alpha (new_layer))
+    gimp_layer_set_lock_alpha (new_layer, FALSE, FALSE);
 
   gimp_image_add_layer (new_image, new_layer, NULL, 0, TRUE);