diff --git a/src/proto/gui_photon.pro b/src/proto/gui_photon.pro
index 6a3ff04..0a5041e 100644
--- a/src/proto/gui_photon.pro
+++ b/src/proto/gui_photon.pro
@@ -8,7 +8,7 @@
 void gui_mch_update __ARGS((void));
 int gui_mch_wait_for_chars __ARGS((int wtime));
 char_u *gui_mch_browse __ARGS((int saving, char_u *title, char_u *default_name, char_u *ext, char_u *initdir, char_u *filter));
-int gui_mch_dialog __ARGS((int type, char_u *title, char_u *message, char_u *buttons, int default_button, char_u *textfield));
+int gui_mch_dialog __ARGS((int type, char_u *title, char_u *message, char_u *buttons, int default_button, char_u *textfield, int ex_cmd));
 int gui_mch_get_winpos __ARGS((int *x, int *y));
 void gui_mch_set_winpos __ARGS((int x, int y));
 void gui_mch_set_shellsize __ARGS((int width, int height, int min_width, int min_height, int base_width, int base_height, int direction));