diff --git a/clients/window.c b/clients/window.c
index f15e8c1d..d82640a1 100644
--- a/clients/window.c
+++ b/clients/window.c
@@ -882,7 +882,7 @@ window_has_focus(struct window *window)
 	return window->focus_count > 0;
 }
 
-void
+static void
 window_flush(struct window *window)
 {
 	if (window->cairo_surface)
diff --git a/clients/window.h b/clients/window.h
index b7aca84e..25122d0c 100644
--- a/clients/window.h
+++ b/clients/window.h
@@ -270,9 +270,6 @@ window_get_wl_surface(struct window *window);
 struct wl_shell_surface *
 window_get_wl_shell_surface(struct window *window);
 
-void
-window_flush(struct window *window);
-
 enum window_buffer_type {
 	WINDOW_BUFFER_TYPE_EGL_WINDOW,
 	WINDOW_BUFFER_TYPE_SHM,