+void Double::update_widget()
+{
+ if (!spin_box_)
+ return;
+
+ Glib::VariantBase variant = getter_();
+ assert(variant.gobj());
+
+ double value = Glib::VariantBase::cast_dynamic<Glib::Variant<double>>(
+ variant).get();
+ spin_box_->setValue(value);
+}
+