diff --git a/src/slic3r/GUI/GUI_ObjectList.hpp b/src/slic3r/GUI/GUI_ObjectList.hpp
index ddbbd71462..87be25ed95 100644
--- a/src/slic3r/GUI/GUI_ObjectList.hpp
+++ b/src/slic3r/GUI/GUI_ObjectList.hpp
@@ -12,6 +12,7 @@
 #include "wxExtensions.hpp"
 
 class wxBoxSizer;
+class wxBitmapComboBox;
 class wxMenuItem;
 class ObjectDataViewModel;
 class MenuWithSeparators;