diff --git a/include/mask.cpp b/include/mask.cpp
index b3c90ad57..1cc8bddb9 100755
--- a/include/mask.cpp
+++ b/include/mask.cpp
@@ -68,7 +68,7 @@ void TMask::control_handler(EVENT* ep)
   {
     if (moving_focus == FALSE)
     {
-      if (test_focus_change(win))
+      if (test_focus_change(f->win()))
       {
         ((TRadio_field*)f)->check_radiobutton(win);
         set_focus_win(win, FALSE);