patch 7.4.1873
Problem:    When a callback adds a timer the GUI doesn't use it until later.
            (Ramel Eshed)
Solution:   Return early if a callback adds a timer.
diff --git a/src/globals.h b/src/globals.h
index 369eb54..2e84e57 100644
--- a/src/globals.h
+++ b/src/globals.h
@@ -1635,6 +1635,10 @@
 EXTERN int  in_free_unref_items INIT(= FALSE);
 #endif
 
+#ifdef FEAT_TIMERS
+EXTERN int  did_add_timer INIT(= FALSE);
+#endif
+
 /*
  * Optional Farsi support.  Include it here, so EXTERN and INIT are defined.
  */