[gimp] app: fix prop-gui static range visibility

[Ell <ell src gnome org>]

commit c7599626f4adfea8764b0608298942dae20a0d7f
Author: Ell <ell_se yahoo com>
Date:   Wed Jun 3 10:10:46 2020 +0300

    app: fix prop-gui static range visibility

 app/propgui/gimppropgui-generic.c | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/app/propgui/gimppropgui-generic.c b/app/propgui/gimppropgui-generic.c
index 775caef13c..5aed3ecd81 100644
--- a/app/propgui/gimppropgui-generic.c
+++ b/app/propgui/gimppropgui-generic.c
@@ -223,6 +223,7 @@ _gimp_prop_gui_new_generic (GObject                  *config,
             create_controller_func,
             creator,
             &label_str);
+          gtk_widget_show (spin_scale);
 
           range_label_str = gegl_param_spec_get_property_key (pspec,
                                                               "range-label");