improve relationship between ArdourDialog and Splash on OS X, where window restacking doesn't really work the way we need it to. more complex than anticipated because it seems that destroying a Gtk::Dialog does not emit its hide() or unmap() or unmap_event() signals

gtk2_ardour/ardour_dialog.cc

@@ -34,12 +34,14 @@ sigc::signal<void> ArdourDialog::CloseAllDialogs;
 
 ArdourDialog::ArdourDialog (string title, bool modal, bool use_seperator)
 	: Dialog (title, modal, use_seperator)
+        , _splash_pushed (false)
 {
 	init ();
 }
 
 ArdourDialog::ArdourDialog (Gtk::Window& parent, string title, bool modal, bool use_seperator)
 	: Dialog (title, parent, modal, use_seperator)
+        , _splash_pushed (false)
 {
 	init ();
 	set_position (Gtk::WIN_POS_CENTER_ON_PARENT);
@@ -47,6 +49,13 @@ ArdourDialog::ArdourDialog (Gtk::Window& parent, string title, bool modal, bool
 
 ArdourDialog::~ArdourDialog ()
 {
+        if (_splash_pushed) {
+                Splash* spl = Splash::instance();
+                
+                if (spl) {
+                        spl->pop_front();
+                }
+        }
 }
 
 bool
@@ -73,15 +82,16 @@ ArdourDialog::on_unmap ()
 void
 ArdourDialog::on_show ()
 {
+	Dialog::on_show ();
+
 	// never allow the splash screen to obscure any dialog
 
 	Splash* spl = Splash::instance();
 
-	if (spl) {
+	if (spl && spl->is_visible()) {
 		spl->pop_back_for (*this);
+                _splash_pushed = true;
 	}
-
-	Dialog::on_show ();
 }
 
 void

gtk2_ardour/ardour_dialog.h

@@ -46,6 +46,7 @@ class ArdourDialog : public Gtk::Dialog, public ARDOUR::SessionHandlePtr
 	static void close_all_dialogs () { CloseAllDialogs(); }
 
   private:
+        bool _splash_pushed;
 	void init ();
 
 	static sigc::signal<void> CloseAllDialogs;

gtk2_ardour/ardour_ui.cc

@@ -3771,12 +3771,14 @@ audio may be played at the wrong sample rate.\n"), desired, PROGRAM_NAME, actual
 	image->show();
 	hbox->show();
 
-	switch (dialog.run ()) {
+	switch (dialog.run()) {
 	case RESPONSE_ACCEPT:
 		return 0;
 	default:
-		return 1;
+                break;
 	}
+
+        return 1;
 }
 
 

gtk2_ardour/splash.cc

@@ -25,6 +25,10 @@
 #include "ardour/ardour.h"
 #include "ardour/filesystem_paths.h"
 
+#ifdef check
+#undef check
+#endif
+
 #include "gui_thread.h"
 #include "splash.h"
 
@@ -96,15 +100,33 @@ Splash::~Splash ()
 void
 Splash::pop_back_for (Gtk::Window& win)
 {
+#ifdef __APPLE__
+        /* April 2013: window layering on OS X is a bit different to X Window. at present,
+           the "restack()" functionality in GDK will only operate on windows in the same
+           "level" (e.g. two normal top level windows, or two utility windows) and will not
+           work across them. The splashscreen is on its own "StatusWindowLevel" so restacking 
+           is not going to work.
+
+           So for OS X, we just hide ourselves.
+        */
+        hide();
+#else
 	set_keep_above (false);
 	get_window()->restack (win.get_window(), false);
-	win.signal_hide().connect (sigc::mem_fun (*this, &Splash::pop_front));
+#endif
 }
 
 void
 Splash::pop_front ()
 {
+
+#ifdef __APPLE__
+        if (get_window()) {
+                show ();
+        }
+#else
 	set_keep_above (true);
+#endif
 }
 
 void