diff --git a/gtk2_ardour/lv2_plugin_ui.cc b/gtk2_ardour/lv2_plugin_ui.cc
index 94b6ded7d9..70466d478d 100644
--- a/gtk2_ardour/lv2_plugin_ui.cc
+++ b/gtk2_ardour/lv2_plugin_ui.cc
@@ -250,7 +250,7 @@ LV2PluginUI::queue_port_update()
 void
 LV2PluginUI::output_update()
 {
-	//cout << "output_update" << endl;
+	//std::cout << "output_update" << std::endl;
 	if (_external_ui_ptr) {
 		LV2_EXTERNAL_UI_RUN(_external_ui_ptr);
 		if (_lv2->is_external_kx() && !_external_ui_ptr) {
@@ -590,7 +590,7 @@ LV2PluginUI::is_update_wanted(uint32_t /*index*/)
 bool
 LV2PluginUI::on_window_show(const std::string& title)
 {
-	//cout << "on_window_show - " << title << endl; flush(cout);
+	//std::cout << "on_window_show - " << title << std::endl;// flush(cout);
 
 	if (_lv2->is_external_ui()) {
 		if (_external_ui_ptr) {
@@ -645,3 +645,15 @@ LV2PluginUI::on_window_hide()
 		lv2ui_free();
 	}
 }
+
+bool
+LV2PluginUI::is_external () const
+{
+	return _lv2->is_external_ui ();
+}
+
+bool
+LV2PluginUI::is_external_visible () const
+{
+	return _external_ui_ptr != 0;
+}
diff --git a/gtk2_ardour/lv2_plugin_ui.h b/gtk2_ardour/lv2_plugin_ui.h
index 51b2d4b061..217148d20d 100644
--- a/gtk2_ardour/lv2_plugin_ui.h
+++ b/gtk2_ardour/lv2_plugin_ui.h
@@ -66,6 +66,9 @@ public:
 	bool start_updating(GdkEventAny*);
 	bool stop_updating(GdkEventAny*);
 
+	bool is_external () const;
+	bool is_external_visible () const;
+
 	int package (Gtk::Window&);
 	void grab_focus ();
 
diff --git a/gtk2_ardour/plugin_ui.h b/gtk2_ardour/plugin_ui.h
index c6e4ed915a..2963a6f7a9 100644
--- a/gtk2_ardour/plugin_ui.h
+++ b/gtk2_ardour/plugin_ui.h
@@ -100,6 +100,9 @@ public:
 	virtual bool start_updating(GdkEventAny*) = 0;
 	virtual bool stop_updating(GdkEventAny*) = 0;
 
+	virtual bool is_external () const { return false; }
+	virtual bool is_external_visible () const { return false; }
+
 	virtual void activate () {}
 	virtual void deactivate () {}
 
diff --git a/gtk2_ardour/processor_box.cc b/gtk2_ardour/processor_box.cc
index defe87e79a..705ae44fd5 100644
--- a/gtk2_ardour/processor_box.cc
+++ b/gtk2_ardour/processor_box.cc
@@ -4787,12 +4787,36 @@ ProcessorWindowProxy::session_handle()
 	/* we don't care */
 	return 0;
 }
+bool
+ProcessorWindowProxy::visible () const
+{
+	PluginUIWindow* puiw = dynamic_cast<PluginUIWindow*> (_window);
+	if (puiw && puiw->pluginui().is_external ()) {
+		return puiw->pluginui().is_external_visible ();
+	}
+	return WM::ProxyBase::visible ();
+}
+
+bool
+ProcessorWindowProxy::fully_visible () const
+{
+	PluginUIWindow* puiw = dynamic_cast<PluginUIWindow*> (_window);
+	if (puiw && puiw->pluginui().is_external ()) {
+		return puiw->pluginui().is_external_visible ();
+	}
+	return WM::ProxyBase::fully_visible ();
+}
 
 XMLNode&
 ProcessorWindowProxy::get_state () const
 {
+	PluginUIWindow* puiw = dynamic_cast<PluginUIWindow*> (_window);
+
 	XMLNode *node;
 	node = &ProxyBase::get_state();
+	if (puiw && puiw->pluginui().is_external ()) {
+		node->set_property (X_("visible"), puiw->pluginui().is_external_visible ());
+	}
 	node->set_property (X_("custom-ui"), is_custom);
 	return *node;
 }
@@ -4844,7 +4868,7 @@ ProcessorWindowProxy::get (bool create)
 
 		if (_window) {
 			setup ();
-			_window->show_all ();
+			_window->show_all (); // XXX
 		}
 	}
 	return _window;
diff --git a/gtk2_ardour/processor_box.h b/gtk2_ardour/processor_box.h
index 5c238f3feb..876a9ccc2f 100644
--- a/gtk2_ardour/processor_box.h
+++ b/gtk2_ardour/processor_box.h
@@ -105,6 +105,9 @@ public:
 	int set_state (const XMLNode&, int);
 	XMLNode& get_state () const;
 
+	bool visible() const;
+	bool fully_visible() const;
+
 private:
 	ProcessorBox* _processor_box;
 	std::weak_ptr<ARDOUR::Processor> _processor;