diff --git a/app/operations/gimp-operation-config.c b/app/operations/gimp-operation-config.c
index 13067dc354..cc5bf4a044 100644
--- a/app/operations/gimp-operation-config.c
+++ b/app/operations/gimp-operation-config.c
@@ -618,6 +618,51 @@ gimp_operation_config_connect_node (GimpObject *config,
   g_free (pspecs);
 }
 
+GParamSpec **
+gimp_operation_config_list_properties (GimpObject  *config,
+                                       GType        owner_type,
+                                       GParamFlags  flags,
+                                       guint       *n_pspecs)
+{
+  GParamSpec **param_specs;
+  guint        n_param_specs;
+  gint         i, j;
+
+  g_return_val_if_fail (GIMP_IS_OBJECT (config), NULL);
+
+  param_specs = g_object_class_list_properties (G_OBJECT_GET_CLASS (config),
+                                                &n_param_specs);
+
+  for (i = 0, j = 0; i < n_param_specs; i++)
+    {
+      GParamSpec *pspec = param_specs[i];
+
+      /*  ignore properties of parent classes of owner_type  */
+      if (! g_type_is_a (pspec->owner_type, owner_type))
+        continue;
+
+      if (flags && ((pspec->flags & flags) != flags))
+        continue;
+
+      if (gimp_gegl_param_spec_has_key (pspec, "role", "output-extent"))
+        continue;
+
+      param_specs[j] = param_specs[i];
+      j++;
+    }
+
+  if (n_pspecs)
+    *n_pspecs = j;
+
+  if (j == 0)
+    {
+      g_free (param_specs);
+      param_specs = NULL;
+    }
+
+  return param_specs;
+}
+
 
 /*  private functions  */
 
diff --git a/app/operations/gimp-operation-config.h b/app/operations/gimp-operation-config.h
index dfd84a4042..09d39974bd 100644
--- a/app/operations/gimp-operation-config.h
+++ b/app/operations/gimp-operation-config.h
@@ -44,5 +44,10 @@ void            gimp_operation_config_sync_node     (GimpObject    *config,
 void            gimp_operation_config_connect_node  (GimpObject    *config,
                                                      GeglNode      *node);
 
+GParamSpec ** gimp_operation_config_list_properties (GimpObject   *config,
+                                                     GType         owner_type,
+                                                     GParamFlags   flags,
+                                                     guint        *n_pspecs);
+
 
 #endif /* __GIMP_OPERATION_CONFIG_H__ */
diff --git a/app/propgui/gimppropgui.c b/app/propgui/gimppropgui.c
index 175c9f467f..1444aca71e 100644
--- a/app/propgui/gimppropgui.c
+++ b/app/propgui/gimppropgui.c
@@ -37,6 +37,8 @@
 
 #include "gegl/gimp-gegl-utils.h"
 
+#include "operations/gimp-operation-config.h"
+
 #include "core/gimpcontext.h"
 
 #include "widgets/gimpcolorpanel.h"
@@ -488,37 +490,18 @@ gimp_prop_gui_new (GObject                  *config,
   GtkWidget    *gui = NULL;
   GParamSpec  **param_specs;
   guint         n_param_specs;
-  gint          i, j;
 
   g_return_val_if_fail (G_IS_OBJECT (config), NULL);
   g_return_val_if_fail (GIMP_IS_CONTEXT (context), NULL);
 
-  param_specs = g_object_class_list_properties (G_OBJECT_GET_CLASS (config),
-                                                &n_param_specs);
+  param_specs = gimp_operation_config_list_properties (GIMP_OBJECT (config),
+                                                       owner_type, flags,
+                                                       &n_param_specs);
 
-  for (i = 0, j = 0; i < n_param_specs; i++)
-    {
-      GParamSpec *pspec = param_specs[i];
-
-      /*  ignore properties of parent classes of owner_type  */
-      if (! g_type_is_a (pspec->owner_type, owner_type))
-        continue;
-
-      if (flags && ((pspec->flags & flags) != flags))
-        continue;
-
-      if (HAS_KEY (pspec, "role", "output-extent"))
-        continue;
-
-      param_specs[j] = param_specs[i];
-      j++;
-    }
-
-  n_param_specs = j;
-
-  if (n_param_specs > 0)
+  if (param_specs)
     {
       const gchar *config_type_name = G_OBJECT_TYPE_NAME (config);
+      gint         i;
 
       for (i = 0; i < G_N_ELEMENTS (gui_new_funcs); i++)
         {
@@ -539,6 +522,8 @@ gimp_prop_gui_new (GObject                  *config,
               break;
             }
         }
+
+      g_free (param_specs);
     }
   else
     {
@@ -549,8 +534,6 @@ gimp_prop_gui_new (GObject                  *config,
       gtk_misc_set_padding (GTK_MISC (gui), 0, 4);
     }
 
-  g_free (param_specs);
-
   return gui;
 }