a bunch of stuff to make tab/window switching work better, and provide Alt-m to toggle between editor+mixer in a sane way

gtk2_ardour/ardour.keys.in

@@ -228,6 +228,7 @@ This mode provides many different operations on both regions and control points,
 @sess|Main/AddTrackBus|<@PRIMARY@><@TERTIARY@>n|add track(s) or bus(ses)
 @sess|Main/New|<@PRIMARY@>n|open a new session
 @wvis|Window/toggle-midi-connection-manager|<@SECONDARY@><@TERTIARY@>m|toggle global midi patchbay
+@wvis|Common/toggle-editor-and-mixer|<@SECONDARY@>m|toggle editor & mixer
 
 ;; arrow keys, navigation etc.
 

gtk2_ardour/ardour_ui.h

@@ -376,8 +376,10 @@ class ARDOUR_UI : public Gtkmm2ext::UI, public ARDOUR::SessionHandlePtr
 	void hide_tabbable (Gtkmm2ext::Tabbable*);
 	void detach_tabbable (Gtkmm2ext::Tabbable*);
 	void attach_tabbable (Gtkmm2ext::Tabbable*);
-	void change_tabbable_visibility (Gtkmm2ext::Tabbable*);
-
+	void button_change_tabbable_visibility (Gtkmm2ext::Tabbable*);
+	void key_change_tabbable_visibility (Gtkmm2ext::Tabbable*);
+	void toggle_editor_and_mixer ();
+	
 	void tabbable_state_change (Gtkmm2ext::Tabbable&);
 
 	void toggle_meterbridge ();

gtk2_ardour/ardour_ui_dependents.cc

@@ -87,11 +87,13 @@ ARDOUR_UI::we_have_dependents ()
 	editor->setup_tooltips ();
 	editor->UpdateAllTransportClocks.connect (sigc::mem_fun (*this, &ARDOUR_UI::update_transport_clocks));
 
-	/* catch up on tabbable state */
+	/* catch up on tabbable state, in the right order to leave the editor
+	 * selected by default
+	 */
 
-	tabbable_state_change (*editor);
-	tabbable_state_change (*mixer);
 	tabbable_state_change (*rc_option_editor);
+	tabbable_state_change (*mixer);
+	tabbable_state_change (*editor);
 
 	/* all actions are defined */
 

gtk2_ardour/ardour_ui_dialogs.cc

@@ -329,13 +329,90 @@ ARDOUR_UI::unload_session (bool hide_stuff)
 }
 
 void
-ARDOUR_UI::change_tabbable_visibility (Tabbable* t)
+ARDOUR_UI::toggle_editor_and_mixer ()
+{
+	if (editor->tabbed() && mixer->tabbed()) {
+		if (_tabs.get_current_page() == _tabs.page_num (editor->contents())) {
+			_tabs.set_current_page (_tabs.page_num (mixer->contents()));
+		} else if (_tabs.get_current_page() == _tabs.page_num (mixer->contents())) {
+			_tabs.set_current_page (_tabs.page_num (editor->contents()));
+		} else {
+			/* do nothing */
+		}
+		return;
+	}
+
+	if (editor->tabbed() && !mixer->tabbed()) {
+		if (!editor->fully_visible()) {
+			if (_tabs.get_current_page() == _tabs.page_num (editor->contents())) {
+				mixer->make_visible ();
+			}
+		} else {
+			_main_window.present ();
+		}
+		return;
+	}
+
+	if (mixer->tabbed () && !editor->tabbed()) {
+		if (!editor->fully_visible()) {
+			if (_tabs.get_current_page() == _tabs.page_num (mixer->contents())) {
+				editor->make_visible ();
+			}
+		} else {
+			_main_window.present ();
+		}
+		return;
+	}
+
+	if (editor->fully_visible()) {
+		mixer->make_visible ();
+	} else {
+		editor->make_visible ();
+	}
+}
+
+void
+ARDOUR_UI::key_change_tabbable_visibility (Tabbable* t)
 {
 	if (!t) {
 		return;
 	}
 
-	t->change_visibility();
+	if (t->tabbed()) {
+		_tabs.set_current_page (_tabs.page_num (t->contents()));
+	} else if (!t->fully_visible()) {
+		t->make_visible ();
+	} else {
+		_main_window.present ();
+	}
+}
+
+void
+ARDOUR_UI::button_change_tabbable_visibility (Tabbable* t)
+{
+	/* For many/most users, clicking a button in the main window will make it
+	   the main/front/key window, which will change any stacking relationship they
+	   were trying to modify by clicking on the button in the first
+	   place. This button-aware method knows that click on
+	   a button designed to show/hide a Tabbable that has its own window
+	   will have made that window be obscured (as the main window comes to
+	   the front). We therefore *hide* the Tabbable's window if it is even
+	   partially visible, believing that this is likely because the
+	   Tabbable window used to be front, the user clicked to change that,
+	   and before we even get here, the main window has become front.
+	*/
+
+	if (!t) {
+		return;
+	}
+
+	if (t->tabbed()) {
+		_tabs.set_current_page (_tabs.page_num (t->contents()));
+	} else if (t->visible()) {
+		t->hide();
+	} else {
+		t->make_visible ();
+	}
 }
 
 void
@@ -554,6 +631,10 @@ ARDOUR_UI::tabbable_state_change (Tabbable& t)
 		vis_button->set_active_state (Gtkmm2ext::Off);
 		break;
 	}
+
+	for (std::vector<ArdourButton*>::iterator b = other_vis_buttons.begin(); b != other_vis_buttons.end(); ++b) {
+		(*b)->set_active_state (Gtkmm2ext::Off);
+	}
 }
 
 void

gtk2_ardour/ardour_ui_ed.cc

@@ -242,9 +242,19 @@ ARDOUR_UI::install_actions ()
 	   are for the tab/window control buttons, which have somewhat odd
 	   semantics.
 	*/
-	global_actions.register_action (common_actions, X_("change-editor-visibility"), _("Change"), sigc::bind (sigc::mem_fun (*this, &ARDOUR_UI::change_tabbable_visibility), editor));
-	global_actions.register_action (common_actions, X_("change-mixer-visibility"), _("Change"), sigc::bind (sigc::mem_fun (*this, &ARDOUR_UI::change_tabbable_visibility), mixer));
-	global_actions.register_action (common_actions, X_("change-preferences-visibility"), _("Change"), sigc::bind (sigc::mem_fun (*this, &ARDOUR_UI::change_tabbable_visibility), rc_option_editor));
+	global_actions.register_action (common_actions, X_("change-editor-visibility"), _("Change"), sigc::bind (sigc::mem_fun (*this, &ARDOUR_UI::button_change_tabbable_visibility), editor));
+	global_actions.register_action (common_actions, X_("change-mixer-visibility"), _("Change"), sigc::bind (sigc::mem_fun (*this, &ARDOUR_UI::button_change_tabbable_visibility), mixer));
+	global_actions.register_action (common_actions, X_("change-preferences-visibility"), _("Change"), sigc::bind (sigc::mem_fun (*this, &ARDOUR_UI::button_change_tabbable_visibility), rc_option_editor));
+
+	/* These "change" actions are not intended to be used inside menus, but
+	   are for the tab/window control key bindings, which have somewhat odd
+	   semantics.
+	*/
+	global_actions.register_action (common_actions, X_("key-change-editor-visibility"), _("Change"), sigc::bind (sigc::mem_fun (*this, &ARDOUR_UI::key_change_tabbable_visibility), editor));
+	global_actions.register_action (common_actions, X_("key-change-mixer-visibility"), _("Change"), sigc::bind (sigc::mem_fun (*this, &ARDOUR_UI::key_change_tabbable_visibility), mixer));
+	global_actions.register_action (common_actions, X_("key-change-preferences-visibility"), _("Change"), sigc::bind (sigc::mem_fun (*this, &ARDOUR_UI::key_change_tabbable_visibility), rc_option_editor));
+
+	global_actions.register_action (common_actions, X_("toggle-editor-and-mixer"), _("Toggle Editor & Mixer"), sigc::mem_fun (*this, &ARDOUR_UI::toggle_editor_and_mixer));
 
 	/* windows visibility actions */
 

libs/gtkmm2ext/gtkmm2ext/window_proxy.h

@@ -52,8 +52,8 @@ class LIBGTKMM2EXT_API WindowProxy : public PBD::StatefulDestructible, public vi
 	void present ();
 	void maybe_show ();
 
-	bool visible() const { return _visible; }
-	bool not_visible() const { return !_visible; }
+	bool visible() const;
+	bool fully_visible() const;
 	const std::string& name() const { return _name; }
 	const std::string& menu_name() const { return _menu_name; }
 

libs/gtkmm2ext/tabbable.cc

@@ -188,11 +188,8 @@ Tabbable::change_visibility ()
 	}
 
 	if (_window && (current_toplevel() == _window)) {
-		if (_window->is_visible ()) {
-			_window->hide ();
-		} else {
-			_window->present ();
-		}
+		/* Use WindowProxy method which will rotate then hide */
+		toggle();
 	}
 }
 

libs/gtkmm2ext/window_proxy.cc

@@ -233,6 +233,26 @@ WindowProxy::setup ()
 	set_pos_and_size ();
 }
 
+bool
+WindowProxy::visible() const
+{
+	if (vistracker) {
+		/* update with current state */
+		_visible = vistracker->partially_visible();
+	}
+	return _visible;
+}
+
+bool
+WindowProxy::fully_visible () const
+{
+	if (!vistracker) {
+		/* no vistracker .. no window .. cannot be fully visible */
+		return false;
+	}
+	return vistracker->fully_visible();
+}
+
 void
 WindowProxy::show ()
 {