diff --git a/src/StdSurface8.cpp b/src/StdSurface8.cpp
index 1e608660..158042fa 100644
--- a/src/StdSurface8.cpp
+++ b/src/StdSurface8.cpp
@@ -17,6 +17,7 @@
 
 // a wrapper class to DirectDraw surfaces
 
+#include "C4Group.h"
 #include <Standard.h>
 #include <StdSurface8.h>
 #include <Bitmap256.h>
diff --git a/src/StdSurface8.h b/src/StdSurface8.h
index dee8c9ce..678e0291 100644
--- a/src/StdSurface8.h
+++ b/src/StdSurface8.h
@@ -19,6 +19,7 @@
 
 #pragma once
 
+#include "C4ForwardDeclarations.h"
 #include <Standard.h>
 #include <StdColors.h>