diff --git a/Xext/shape.c b/Xext/shape.c
index 6995c1b18..1630a9ef3 100644
--- a/Xext/shape.c
+++ b/Xext/shape.c
@@ -33,6 +33,7 @@ in this Software without prior written authorization from The Open Group.
 
 #include "dix/dix_priv.h"
 #include "dix/gc_priv.h"
+#include "dix/window_priv.h"
 #include "miext/extinit_priv.h"
 #include "Xext/panoramiX.h"
 #include "Xext/panoramiXsrv.h"
diff --git a/Xi/exevents.c b/Xi/exevents.c
index 2116d6d18..960d1381e 100644
--- a/Xi/exevents.c
+++ b/Xi/exevents.c
@@ -97,6 +97,7 @@ SOFTWARE.
 #include "dix/exevents_priv.h"
 #include "dix/input_priv.h"
 #include "dix/resource_priv.h"
+#include "dix/window_priv.h"
 #include "mi/mi_priv.h"
 #include "os/log_priv.h"
 #include "xkb/xkbsrv_priv.h"
diff --git a/dix/events.c b/dix/events.c
index 415b9ff1b..3058efec7 100644
--- a/dix/events.c
+++ b/dix/events.c
@@ -127,6 +127,7 @@ Equipment Corporation.
 #include "dix/input_priv.h"
 #include "dix/reqhandlers_priv.h"
 #include "dix/resource_priv.h"
+#include "dix/window_priv.h"
 #include "os/bug_priv.h"
 #include "os/client_priv.h"
 #include "os/fmt.h"
diff --git a/dix/grabs.c b/dix/grabs.c
index 883d24822..fafd724e3 100644
--- a/dix/grabs.c
+++ b/dix/grabs.c
@@ -56,6 +56,7 @@ SOFTWARE.
 #include "dix/dixgrabs_priv.h"
 #include "dix/exevents_priv.h"
 #include "dix/resource_priv.h"
+#include "dix/window_priv.h"
 #include "os/auth.h"
 #include "os/client_priv.h"
 
diff --git a/dix/property.c b/dix/property.c
index 43d37ea18..e0456711c 100644
--- a/dix/property.c
+++ b/dix/property.c
@@ -52,6 +52,7 @@ SOFTWARE.
 #include "dix/dix_priv.h"
 #include "dix/input_priv.h"
 #include "dix/property_priv.h"
+#include "dix/window_priv.h"
 #include "Xext/panoramiX.h"
 #include "Xext/panoramiXsrv.h"
 
diff --git a/dix/window_priv.h b/dix/window_priv.h
index 874bc0f8c..cf28b1f70 100644
--- a/dix/window_priv.h
+++ b/dix/window_priv.h
@@ -31,5 +31,14 @@ WindowPtr dixCreateWindow(Window wid,
                           ClientPtr client,
                           VisualID visual,
                           int * error);
+/*
+ * @brief Make sure the window->optional structure exists.
+ *
+ * allocate if window->optional == NULL, otherwise do nothing.
+ *
+ * @param pWin the window to operate on
+ * @return FALSE if allocation failed, otherwise TRUE
+ */
+Bool MakeWindowOptional(WindowPtr pWin);
 
 #endif /* _XSERVER_DIX_WINDOW_PRIV_H */
diff --git a/include/window.h b/include/window.h
index ded5748cd..dffefbdcd 100644
--- a/include/window.h
+++ b/include/window.h
@@ -190,8 +190,6 @@ extern _X_EXPORT WindowPtr FindWindowWithOptional(WindowPtr /*w */ );
 
 extern _X_EXPORT void CheckWindowOptionalNeed(WindowPtr /*w */ );
 
-extern _X_EXPORT Bool MakeWindowOptional(WindowPtr /*pWin */ );
-
 extern _X_EXPORT WindowPtr MoveWindowInStack(WindowPtr /*pWin */ ,
                                              WindowPtr /*pNextSib */ );
 
diff --git a/xfixes/region.c b/xfixes/region.c
index 5928ce5f3..0813ae1f4 100644
--- a/xfixes/region.c
+++ b/xfixes/region.c
@@ -23,6 +23,7 @@
 #include <dix-config.h>
 
 #include "dix/dix_priv.h"
+#include "dix/window_priv.h"
 #include "render/picturestr_priv.h"
 #include "Xext/panoramiX.h"
 #include "Xext/panoramiXsrv.h"