diff -Naur xfce4-power-manager/libdbus/xfpm-dbus-monitor.c xfce4-power-manager/libdbus/xfpm-dbus-monitor.c
--- xfce4-power-manager/libdbus/xfpm-dbus-monitor.c	2019-09-01 23:55:42.454756756 +0700
+++ xfce4-power-manager/libdbus/xfpm-dbus-monitor.c	2019-09-02 00:00:22.800179127 +0700
@@ -34,7 +34,8 @@
 #include "xfpm-dbus-monitor.h"
 #include "xfpm-dbus-marshal.h"
 
-static void xfpm_dbus_monitor_finalize   (GObject *object);
+static void xfpm_dbus_monitor_finalize                (GObject *object);
+static void xfpm_dbus_monitor_free_watch_data_wrapper (void *data, void *userdata);
 
 #define XFPM_DBUS_MONITOR_GET_PRIVATE(o) \
 (G_TYPE_INSTANCE_GET_PRIVATE ((o), XFPM_TYPE_DBUS_MONITOR, XfpmDBusMonitorPrivate))
@@ -265,6 +266,12 @@
     xfpm_dbus_monitor_system  (monitor);
 }
 
+static void
+xfpm_dbus_monitor_free_watch_data_wrapper (void *data, void *userdata)
+{
+    xfpm_dbus_monitor_free_watch_data (data);
+}
+
 static void
 xfpm_dbus_monitor_finalize (GObject *object)
 {
@@ -279,8 +286,8 @@
     g_object_unref (monitor->priv->system_bus);
     g_object_unref (monitor->priv->session_bus);
 
-    g_ptr_array_foreach (monitor->priv->names_array, (GFunc) xfpm_dbus_monitor_free_watch_data, NULL);
-    g_ptr_array_foreach (monitor->priv->services_array, (GFunc) xfpm_dbus_monitor_free_watch_data, NULL);
+    g_ptr_array_foreach (monitor->priv->names_array, (GFunc) xfpm_dbus_monitor_free_watch_data_wrapper, NULL);
+    g_ptr_array_foreach (monitor->priv->services_array, (GFunc) xfpm_dbus_monitor_free_watch_data_wrapper, NULL);
 
     g_ptr_array_free (monitor->priv->names_array, TRUE);
     g_ptr_array_free (monitor->priv->services_array, TRUE);
diff -Naur xfce4-power-manager/src/xfpm-notify.c xfce4-power-manager/src/xfpm-notify.c
--- xfce4-power-manager/src/xfpm-notify.c	2019-09-01 23:55:20.229518815 +0700
+++ xfce4-power-manager/src/xfpm-notify.c	2019-09-02 00:00:04.720814398 +0700
@@ -47,6 +47,7 @@
 #include "xfpm-dbus-monitor.h"
 
 static void xfpm_notify_finalize   (GObject *object);
+static void g_free_wrapper         (void *data, void *userdata);
 
 static NotifyNotification * xfpm_notify_new_notification_internal (const gchar *title,
 								   const gchar *message,
@@ -77,6 +78,12 @@
 
 G_DEFINE_TYPE_WITH_PRIVATE (XfpmNotify, xfpm_notify, G_TYPE_OBJECT)
 
+static void
+g_free_wrapper (void *data, void *userdata)
+{
+    g_free (data);
+}
+
 static void
 xfpm_notify_get_server_caps (XfpmNotify *notify)
 {
@@ -94,7 +101,7 @@
 	if (g_list_find_custom (caps, "actions", (GCompareFunc) g_strcmp0) != NULL)
 	    notify->priv->supports_actions = TRUE;
 
-	g_list_foreach(caps, (GFunc)g_free, NULL);
+	g_list_foreach(caps, (GFunc)g_free_wrapper, NULL);
 	g_list_free(caps);
     }
 }