diff --git a/gtk2_ardour/mac_vst_plugin_ui.h b/gtk2_ardour/mac_vst_plugin_ui.h
index 2082fa8578..535a0c2212 100644
--- a/gtk2_ardour/mac_vst_plugin_ui.h
+++ b/gtk2_ardour/mac_vst_plugin_ui.h
@@ -34,6 +34,14 @@
 
 #include "vst_plugin_ui.h"
 
+class MacVSTPluginUI;
+
+@interface ResizeNotificationObject : NSObject {
+	@private
+		MacVSTPluginUI* plugin_ui;
+}
+@end
+
 class MacVSTPluginUI : public VSTPluginUI
 {
 public:
@@ -46,11 +54,19 @@ public:
 	int package (Gtk::Window &);
 
 	void forward_key_event (GdkEventKey *);
+	void view_resized ();
+
+protected:
+	void lower_box_realized ();
+	bool lower_box_visibility_notify (GdkEventVisibility*);
+	void lower_box_map ();
+	void lower_box_unmap ();
+	void lower_box_size_request (GtkRequisition*);
+	void lower_box_size_allocate (Gtk::Allocation&);
 
 private:
 	int get_XID ();
 	bool idle ();
-	void lower_box_realized ();
 	void set_program ();
 	NSWindow* get_nswindow();
 
@@ -58,4 +74,5 @@ private:
 	NSView*          _ns_view;
 	sigc::connection _idle_connection;
 	PBD::ScopedConnection _program_connection;
+	ResizeNotificationObject* _resize_notifier;
 };
diff --git a/gtk2_ardour/mac_vst_plugin_ui.mm b/gtk2_ardour/mac_vst_plugin_ui.mm
index 5a20af8036..6297525d16 100644
--- a/gtk2_ardour/mac_vst_plugin_ui.mm
+++ b/gtk2_ardour/mac_vst_plugin_ui.mm
@@ -40,6 +40,24 @@ struct ERect{
     short right;
 };
 
+
+@implementation ResizeNotificationObject
+
+- (ResizeNotificationObject*) initWithPluginUI: (MacVSTPluginUI*) vstui
+{
+	self = [ super init ];
+	plugin_ui = vstui;
+	return self;
+}
+
+- (void)viewResized:(NSNotification *)notification
+{
+	(void) notification; // unused
+	plugin_ui->view_resized();
+}
+
+@end
+
 VSTPluginUI*
 create_mac_vst_gui (boost::shared_ptr<PluginInsert> insert)
 {
@@ -55,18 +73,45 @@ MacVSTPluginUI::MacVSTPluginUI (boost::shared_ptr<PluginInsert> pi, boost::share
 {
 	low_box.add_events (Gdk::VISIBILITY_NOTIFY_MASK | Gdk::EXPOSURE_MASK);
 	low_box.signal_realize().connect (mem_fun (this, &MacVSTPluginUI::lower_box_realized));
+	low_box.signal_visibility_notify_event ().connect (mem_fun (this, &MacVSTPluginUI::lower_box_visibility_notify));
+	low_box.signal_size_request ().connect (mem_fun (this, &MacVSTPluginUI::lower_box_size_request));
+	low_box.signal_size_allocate ().connect (mem_fun (this, &MacVSTPluginUI::lower_box_size_allocate));
+	low_box.signal_map ().connect (mem_fun (this, &MacVSTPluginUI::lower_box_map));
+	low_box.signal_unmap ().connect (mem_fun (this, &MacVSTPluginUI::lower_box_unmap));
+
 	pack_start (low_box, true, true);
 	low_box.show ();
+
 	vst->LoadPresetProgram.connect (_program_connection, invalidator (*this), boost::bind (&MacVSTPluginUI::set_program, this), gui_context());
 
+	_ns_view = [[NSView new] retain];
+
+	AEffect* plugin = _vst->state()->plugin;
+	plugin->dispatcher (plugin, effEditOpen, 0, 0, _ns_view, 0.0f);
+	_idle_connection = Glib::signal_idle().connect (sigc::mem_fun (*this, &MacVSTPluginUI::idle));
+
+	_resize_notifier = [[ResizeNotificationObject alloc] initWithPluginUI:this];
+	[[NSNotificationCenter defaultCenter] addObserver:_resize_notifier
+		selector:@selector(viewResized:) name:NSViewFrameDidChangeNotification
+		object:_ns_view];
+
+	NSArray* subviews = [_ns_view subviews];
+	assert ([subviews count] < 2);
+	for (unsigned long i = 0; i < [subviews count]; ++i) {
+		NSView* subview = [subviews objectAtIndex:i];
+		[[NSNotificationCenter defaultCenter] addObserver:_resize_notifier
+			selector:@selector(viewResized:) name:NSViewFrameDidChangeNotification
+			object:subview];
+	}
 }
 
 MacVSTPluginUI::~MacVSTPluginUI ()
 {
-	if (_ns_view) {
-		[_ns_view removeFromSuperview];
-		[_ns_view release];
-	}
+	[[NSNotificationCenter defaultCenter] removeObserver:_resize_notifier];
+	[_resize_notifier release];
+
+	[_ns_view removeFromSuperview];
+	[_ns_view release];
 
 	AEffect* plugin = _vst->state()->plugin;
 	plugin->dispatcher (plugin, effEditClose, 0, 0, 0, 0.0f);
@@ -114,35 +159,68 @@ MacVSTPluginUI::lower_box_realized ()
 	[win setAutodisplay:1]; // turn off GTK stuff for this window
 
 	NSView* view = gdk_quartz_window_get_nsview (low_box.get_window()->gobj());
-	_ns_view = [[NSView new] retain];
 	[view addSubview:_ns_view];
+	low_box.queue_resize ();
+}
 
-	AEffect* plugin = _vst->state()->plugin;
-	plugin->dispatcher (plugin, effEditOpen, 0, 0, _ns_view, 0.0f);
+bool
+MacVSTPluginUI::lower_box_visibility_notify (GdkEventVisibility* ev)
+{
+	return false;
+}
+void
+MacVSTPluginUI::lower_box_map ()
+{
+	[_ns_view setHidden:0];
+}
 
+void
+MacVSTPluginUI::lower_box_unmap ()
+{
+	[_ns_view setHidden:1];
+}
+
+void
+MacVSTPluginUI::lower_box_size_request (GtkRequisition* requisition)
+{
 	struct ERect* er = NULL;
+	AEffect* plugin = _vst->state()->plugin;
 	plugin->dispatcher (plugin, effEditGetRect, 0, 0, &er, 0 );
 	if (er) {
-		int req_width = er->right - er->left;
-		int req_height = er->bottom - er->top;
-
-		low_box.set_size_request (req_width, req_height);
-
-		gint xx, yy;
-		gtk_widget_translate_coordinates(
-				GTK_WIDGET(low_box.gobj()),
-				GTK_WIDGET(low_box.get_parent()->gobj()),
-				8, 6, &xx, &yy);
-		[_ns_view setFrame:NSMakeRect(xx, yy, req_width, req_height)];
+		requisition->width  = er->right - er->left;
+		requisition->height = er->bottom - er->top;
+	} else {
+		requisition->width  = 600;
+		requisition->height = 400;
 	}
+}
 
-	_idle_connection = Glib::signal_idle().connect (sigc::mem_fun (*this, &MacVSTPluginUI::idle));
+void
+MacVSTPluginUI::lower_box_size_allocate (Gtk::Allocation& allocation)
+{
+	gint xx, yy;
+	gtk_widget_translate_coordinates(
+			GTK_WIDGET(low_box.gobj()),
+			GTK_WIDGET(low_box.get_parent()->gobj()),
+			8, 6, &xx, &yy);
+	[_ns_view setFrame:NSMakeRect (xx, yy, allocation.get_width (), allocation.get_height ())];
+	NSArray* subviews = [_ns_view subviews];
+	for (unsigned long i = 0; i < [subviews count]; ++i) {
+		NSView* subview = [subviews objectAtIndex:i];
+		[subview setFrame:NSMakeRect (0, 0, allocation.get_width (), allocation.get_height ())];
+	}
+}
+
+void
+MacVSTPluginUI::view_resized ()
+{
+	low_box.queue_resize ();
 }
 
 int
 MacVSTPluginUI::get_XID ()
 {
-	return _vst->state()->xid;
+	return _vst->state()->xid; // unused
 }
 
 bool