diff --git a/src/gtk/settings.cpp b/src/gtk/settings.cpp
index 8bddf252fc..3834344945 100644
--- a/src/gtk/settings.cpp
+++ b/src/gtk/settings.cpp
@@ -974,6 +974,11 @@ wxIMPLEMENT_DYNAMIC_CLASS(wxSystemSettingsModule, wxModule);
 void wxSystemSettingsModule::OnExit()
 {
 #ifdef __WXGTK3__
+    GtkSettings* settings = gtk_settings_get_default();
+    g_signal_handlers_disconnect_by_func(settings,
+        (void*)notify_gtk_theme_name, NULL);
+    g_signal_handlers_disconnect_by_func(settings,
+        (void*)notify_gtk_font_name, NULL);
 #else
     if (gs_tlw_parent)
         gtk_widget_destroy(gs_tlw_parent);
diff --git a/src/gtk/win_gtk.cpp b/src/gtk/win_gtk.cpp
index 49f0b348dc..192e212260 100644
--- a/src/gtk/win_gtk.cpp
+++ b/src/gtk/win_gtk.cpp
@@ -334,6 +334,13 @@ GType wxPizza::type()
     static GType type;
     if (type == 0)
     {
+        const char* name = "wxPizza";
+        char buf[30];
+        for (unsigned i = 0; g_type_from_name(name); i++)
+        {
+            g_snprintf(buf, sizeof(buf), "wxPizza%u", i);
+            name = buf;
+        }
         const GTypeInfo info = {
             sizeof(wxPizzaClass),
             NULL, NULL,
@@ -343,7 +350,7 @@ GType wxPizza::type()
             NULL, NULL
         };
         type = g_type_register_static(
-            GTK_TYPE_FIXED, "wxPizza", &info, GTypeFlags(0));
+            GTK_TYPE_FIXED, name, &info, GTypeFlags(0));
 #ifdef __WXGTK3__
         const GInterfaceInfo interface_info = { NULL, NULL, NULL };
         g_type_add_interface_static(type, GTK_TYPE_SCROLLABLE, &interface_info);