diff --git a/src/slic3r/GUI/Preferences.hpp b/src/slic3r/GUI/Preferences.hpp
index ec35bc2a4..738e805b2 100644
--- a/src/slic3r/GUI/Preferences.hpp
+++ b/src/slic3r/GUI/Preferences.hpp
@@ -7,6 +7,8 @@
 #include <wx/dialog.h>
 #include <map>
 
+class wxRadioBox;
+
 namespace Slic3r {
 namespace GUI {