diff --git a/app/operations/gimpoperationborder.c b/app/operations/gimpoperationborder.c
index b25c46eed4..3146154204 100644
--- a/app/operations/gimpoperationborder.c
+++ b/app/operations/gimpoperationborder.c
@@ -91,6 +91,7 @@ gimp_operation_border_class_init (GimpOperationBorderClass *klass)
   operation_class->prepare                 = gimp_operation_border_prepare;
   operation_class->get_required_for_output = gimp_operation_border_get_required_for_output;
   operation_class->get_cached_region       = gimp_operation_border_get_cached_region;
+  operation_class->threaded                = FALSE;
 
   filter_class->process                    = gimp_operation_border_process;
 
diff --git a/app/operations/gimpoperationgrow.c b/app/operations/gimpoperationgrow.c
index dbd9ab4764..6ed26552d6 100644
--- a/app/operations/gimpoperationgrow.c
+++ b/app/operations/gimpoperationgrow.c
@@ -90,6 +90,7 @@ gimp_operation_grow_class_init (GimpOperationGrowClass *klass)
   operation_class->prepare                 = gimp_operation_grow_prepare;
   operation_class->get_required_for_output = gimp_operation_grow_get_required_for_output;
   operation_class->get_cached_region       = gimp_operation_grow_get_cached_region;
+  operation_class->threaded                = FALSE;
 
   filter_class->process                    = gimp_operation_grow_process;
 
diff --git a/app/operations/gimpoperationshrink.c b/app/operations/gimpoperationshrink.c
index 67a25b02ea..86a318d269 100644
--- a/app/operations/gimpoperationshrink.c
+++ b/app/operations/gimpoperationshrink.c
@@ -91,6 +91,7 @@ gimp_operation_shrink_class_init (GimpOperationShrinkClass *klass)
   operation_class->prepare                 = gimp_operation_shrink_prepare;
   operation_class->get_required_for_output = gimp_operation_shrink_get_required_for_output;
   operation_class->get_cached_region       = gimp_operation_shrink_get_cached_region;
+  operation_class->threaded                = FALSE;
 
   filter_class->process                    = gimp_operation_shrink_process;