diff --git a/src/proto/popupwin.pro b/src/proto/popupwin.pro
index 0a5db0c..145cbea 100644
--- a/src/proto/popupwin.pro
+++ b/src/proto/popupwin.pro
@@ -4,6 +4,7 @@
 void popup_start_drag(win_T *wp);
 void popup_drag(win_T *wp);
 void popup_set_firstline(win_T *wp);
+int popup_is_in_scrollbar(win_T *wp, int row, int col);
 void popup_handle_scrollbar_click(win_T *wp, int row, int col);
 int popup_height(win_T *wp);
 int popup_width(win_T *wp);