diff -ur xfce4-screensaver-0.1.9-orig/src/gs-listener-dbus.c xfce4-screensaver-0.1.9/src/gs-listener-dbus.c
--- xfce4-screensaver-0.1.9-orig/src/gs-listener-dbus.c	2020-03-23 02:35:47.000000000 +0300
+++ xfce4-screensaver-0.1.9/src/gs-listener-dbus.c	2020-03-29 23:40:01.192265252 +0300
@@ -1305,14 +1305,32 @@
     g_return_val_if_fail (message != NULL, DBUS_HANDLER_RESULT_NOT_YET_HANDLED);
 
     if (dbus_message_is_method_call (message, GS_LISTENER_SERVICE, "Lock")) {
+        DBusMessage *reply = dbus_message_new_method_return (message);
+        if (reply) {
+            dbus_connection_send (connection, reply, NULL);
+            dbus_message_unref (reply);
+        }
+
         g_signal_emit (listener, signals[LOCK], 0);
         return DBUS_HANDLER_RESULT_HANDLED;
     }
     if (dbus_message_is_method_call (message, GS_LISTENER_SERVICE, "Quit")) {
+        DBusMessage *reply = dbus_message_new_method_return (message);
+        if (reply) {
+            dbus_connection_send (connection, reply, NULL);
+            dbus_message_unref (reply);
+        }
+
         g_signal_emit (listener, signals[QUIT], 0);
         return DBUS_HANDLER_RESULT_HANDLED;
     }
     if (dbus_message_is_method_call (message, GS_LISTENER_SERVICE, "Cycle")) {
+        DBusMessage *reply = dbus_message_new_method_return (message);
+        if (reply) {
+            dbus_connection_send (connection, reply, NULL);
+            dbus_message_unref (reply);
+        }
+
         g_signal_emit (listener, signals[CYCLE], 0);
         return DBUS_HANDLER_RESULT_HANDLED;
     }
@@ -1344,6 +1362,11 @@
         return listener_show_message (listener, connection, message);
     }
     if (dbus_message_is_method_call (message, GS_LISTENER_SERVICE, "SimulateUserActivity")) {
+        DBusMessage *reply = dbus_message_new_method_return (message);
+        if (reply) {
+            dbus_connection_send (connection, reply, NULL);
+            dbus_message_unref (reply);
+        }
         g_signal_emit (listener, signals[SIMULATE_USER_ACTIVITY], 0);
         return DBUS_HANDLER_RESULT_HANDLED;
     }
@@ -1753,7 +1776,7 @@
             listener_service_deleted (listener, message);
         }
     } else {
-        return listener_dbus_handle_session_message (connection, message, user_data, FALSE);
+        return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
     }
 
     return DBUS_HANDLER_RESULT_HANDLED;
@@ -1778,7 +1801,7 @@
 
         g_timeout_add (10000, (GSourceFunc)reinit_dbus, listener);
     } else {
-        return listener_dbus_handle_system_message (connection, message, user_data, FALSE);
+        return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
     }
 
     return DBUS_HANDLER_RESULT_HANDLED;