diff --git a/src/slic3r/GUI/Tab.cpp b/src/slic3r/GUI/Tab.cpp
index 6916c04a5..c68de4984 100644
--- a/src/slic3r/GUI/Tab.cpp
+++ b/src/slic3r/GUI/Tab.cpp
@@ -3841,7 +3841,7 @@ bool Tab::validate_custom_gcodes()
         assert(opt_group->opt_map().size() == 1);
         std::string key = opt_group->opt_map().begin()->first;
         std::string value = boost::any_cast<std::string>(opt_group->get_value(key));
-        std::string config_value = m_type == Preset::TYPE_FILAMENT ? m_config->opt_string(key, unsigned int(0)) : m_config->opt_string(key);
+        std::string config_value = m_type == Preset::TYPE_FILAMENT ? m_config->opt_string(key, 0u) : m_config->opt_string(key);
         valid &= validate_custom_gcode(opt_group->title, value);
         Field* field = opt_group->get_field(key);
         TextCtrl* text_ctrl = dynamic_cast<TextCtrl*>(field);