diff --git a/src/slic3r/GUI/GLSelectionRectangle.hpp b/src/slic3r/GUI/GLSelectionRectangle.hpp
index ef1f831cc..2422066e0 100644
--- a/src/slic3r/GUI/GLSelectionRectangle.hpp
+++ b/src/slic3r/GUI/GLSelectionRectangle.hpp
@@ -6,7 +6,7 @@
 namespace Slic3r {
 namespace GUI {
     
-class Camera;
+struct Camera;
 
 class GLSelectionRectangle {
 public: