diff --git a/src/libslic3r/AppConfig.hpp b/src/libslic3r/AppConfig.hpp
index ffa22bd7de..36b89f5b05 100644
--- a/src/libslic3r/AppConfig.hpp
+++ b/src/libslic3r/AppConfig.hpp
@@ -36,6 +36,7 @@ using namespace nlohmann;
 #define SETTING_OPENGL_SHOW_FPS_OVERLAY "opengl_show_fps_overlay"
 #define SETTING_OPENGL_REALISTIC_MODE "opengl_realistic_mode"
 #define SETTING_OPENGL_REALISTIC_PHONG "opengl_realistic_phong"
+#define SETTING_OPENGL_SHADING_MODEL "opengl_shading_model"
 #define SETTING_OPENGL_PHONG_BASIC_PLATE_SHADOWS "opengl_phong_basic_plate_shadows"
 #define SETTING_OPENGL_PHONG_SSAO "opengl_phong_ssao"