diff --git a/src/proto/ex_cmds.pro b/src/proto/ex_cmds.pro
index a4d60ba..3693cf4 100644
--- a/src/proto/ex_cmds.pro
+++ b/src/proto/ex_cmds.pro
@@ -35,7 +35,7 @@
 char_u *get_old_sub(void);
 void set_old_sub(char_u *val);
 void free_old_sub(void);
-int prepare_tagpreview(int undo_sync, int use_previewpopup, int use_popup);
+int prepare_tagpreview(int undo_sync, int use_previewpopup, use_popup_T use_popup);
 void ex_help(exarg_T *eap);
 void ex_helpclose(exarg_T *eap);
 char_u *check_help_lang(char_u *arg);