diff --git a/src/slic3r/GUI/GUI_ObjectLayers.hpp b/src/slic3r/GUI/GUI_ObjectLayers.hpp
index aa09e64a6..0b404be4f 100644
--- a/src/slic3r/GUI/GUI_ObjectLayers.hpp
+++ b/src/slic3r/GUI/GUI_ObjectLayers.hpp
@@ -9,13 +9,13 @@ class wxBoxSizer;
 namespace Slic3r {
 class ModelObject;
 
-namespace GUI {
-class ConfigOptionsGroup;
-
 typedef double                                              coordf_t;
 typedef std::pair<coordf_t, coordf_t>                       t_layer_height_range;
 typedef std::map<t_layer_height_range, DynamicPrintConfig>  t_layer_config_ranges;
 
+namespace GUI {
+class ConfigOptionsGroup;
+
 class LayerRangeEditor : public wxTextCtrl
 {
     bool                m_enter_pressed     { false };