diff --git a/src/proto/window.pro b/src/proto/window.pro
index 5316f95..5141b05 100644
--- a/src/proto/window.pro
+++ b/src/proto/window.pro
@@ -18,6 +18,7 @@
 void close_windows(buf_T *buf, int keep_curwin);
 int one_window(void);
 int win_close(win_T *win, int free_buf);
+void may_make_initial_scroll_size_snapshot(void);
 void may_trigger_winscrolled(void);
 void win_close_othertab(win_T *win, int free_buf, tabpage_T *tp);
 void win_free_all(void);