diff --git a/src/proto/buffer.pro b/src/proto/buffer.pro
index 5e1aa7a..1748fb5 100644
--- a/src/proto/buffer.pro
+++ b/src/proto/buffer.pro
@@ -61,6 +61,7 @@
 int bt_terminal(buf_T *buf);
 int bt_help(buf_T *buf);
 int bt_prompt(buf_T *buf);
+int bt_popup(buf_T *buf);
 int bt_nofile(buf_T *buf);
 int bt_dontwrite(buf_T *buf);
 int bt_dontwrite_msg(buf_T *buf);