diff --git a/src/proto/window.pro b/src/proto/window.pro
index 4c9bddd..24ab0ec 100644
--- a/src/proto/window.pro
+++ b/src/proto/window.pro
@@ -10,6 +10,7 @@
 int make_windows(int count, int vertical);
 void win_move_after(win_T *win1, win_T *win2);
 void win_equal(win_T *next_curwin, int current, int dir);
+void entering_window(win_T *win);
 void close_windows(buf_T *buf, int keep_curwin);
 int one_window(void);
 int win_close(win_T *win, int free_buf);