Unload drop menu window when countdown expires

src/c/main.c

@@ -604,7 +604,10 @@ static void alarm_tick_handler(struct tm *tick_time, TimeUnits units_changed) {
 	}
 	snprintf(s_countdown_buf, sizeof(s_countdown_buf), "%03u", s_countdown_int);
 	text_layer_set_text(s_countdown_txt_layer, s_countdown_buf);
-	if (s_countdown_int == 0 && !s_door_anim) {    // punish user and demote if countdown expires
+	if (s_countdown_int == 0 && !s_door_anim) { // punish user and demote if countdown expires
+		if (s_drop_menu_layer) {                // layer is null'd when window is unloaded
+			window_stack_remove(s_drop_window, true);
+		}
 		s_continuous_zap_on_first_triangle = true; // begin zapping once the first countdown expires
 		send_zap();
 		s_secs_since_last_input = 10;