Introduce theme preference "transients follow front" which, when enabled,

sets transient windows to be transients for the front window when switching
between the editor and mixer. This is the current behavior on non-osx
builds.
When disabled, there is no reparenting of transient windows. This is the
current behavior on osx.
This preference defaults to off.

Also fix "all windows are dialogs" checkbox being out of sync with the ui
state.

gtk2_ardour/ardour_ui_dialogs.cc

@@ -336,7 +336,9 @@ ARDOUR_UI::goto_editor_window ()
 	editor->show_window ();
 	editor->present ();
 	/* mixer should now be on top */
-	WM::Manager::instance().set_transient_for (editor);
+	if (ARDOUR_UI::config()->get_transients_follow_front()) {
+		WM::Manager::instance().set_transient_for (editor);
+	}
 	_mixer_on_top = false;
 }
 
@@ -365,7 +367,9 @@ ARDOUR_UI::goto_mixer_window ()
 	mixer->show_window ();
 	mixer->present ();
 	/* mixer should now be on top */
-	WM::Manager::instance().set_transient_for (mixer);
+	if (ARDOUR_UI::config()->get_transients_follow_front()) {
+		WM::Manager::instance().set_transient_for (mixer);
+	}
 	_mixer_on_top = true;
 }
 

gtk2_ardour/default_ui_config.in

@@ -9,6 +9,7 @@
     <Option name="waveform-gradient-depth" value="0"/>
     <Option name="timeline-item-gradient-depth" value="0.5"/>
     <Option name="all-floating-windows-are-dialogs" value="0"/>
+    <Option name="transients-follow-front" value="0"/>
     <Option name="color-regions-using-track-color" value="0"/>
     <Option name="show-waveform-clipping" value="1"/>
     <Option name="lock-gui-after-seconds" value="0"/>

gtk2_ardour/theme_manager.cc

@@ -74,6 +74,7 @@ ThemeManager::ThemeManager()
 	, timeline_item_gradient_depth (0, 1.0, 0.05)
 	, timeline_item_gradient_depth_label (_("Timeline item gradient depth"))
 	, all_dialogs (_("All floating windows are dialogs"))
+	, transients_follow_front (_("Transient windows follow front window."))
 	, icon_set_label (_("Icon Set"))
 	, palette_viewport (*palette_scroller.get_hadjustment(), *palette_scroller.get_vadjustment())
 	, palette_group (0)
@@ -115,6 +116,7 @@ ThemeManager::ThemeManager()
 	pack_start (reset_button, PACK_SHRINK);
 #ifndef __APPLE__
 	pack_start (all_dialogs, PACK_SHRINK);
+	pack_start (transients_follow_front, PACK_SHRINK);
 #endif
 	pack_start (flat_buttons, PACK_SHRINK);
 	pack_start (blink_rec_button, PACK_SHRINK);
@@ -184,12 +186,16 @@ ThemeManager::ThemeManager()
 	waveform_gradient_depth.signal_value_changed().connect (sigc::mem_fun (*this, &ThemeManager::on_waveform_gradient_depth_change));
 	timeline_item_gradient_depth.signal_value_changed().connect (sigc::mem_fun (*this, &ThemeManager::on_timeline_item_gradient_depth_change));
 	all_dialogs.signal_toggled().connect (sigc::mem_fun (*this, &ThemeManager::on_all_dialogs_toggled));
+	transients_follow_front.signal_toggled().connect (sigc::mem_fun (*this, &ThemeManager::on_transients_follow_front_toggled));
 	icon_set_dropdown.signal_changed().connect (sigc::mem_fun (*this, &ThemeManager::on_icon_set_changed));
 
 	Gtkmm2ext::UI::instance()->set_tip (all_dialogs, 
 					    string_compose (_("Mark all floating windows to be type \"Dialog\" rather than using \"Utility\" for some.\n"
 							      "This may help with some window managers. This requires a restart of %1 to take effect"),
 							    PROGRAM_NAME));
+	Gtkmm2ext::UI::instance()->set_tip (transients_follow_front, 
+					    string_compose (_("Make transient windows follow the front window when toggling between the editor and mixer.\n"
+							      "This requires a restart of %1 to take effect"), PROGRAM_NAME));
 
 	set_size_request (-1, 400);
 	/* no need to call setup_palette() here, it will be done when its size is allocated */
@@ -297,6 +303,12 @@ ThemeManager::on_all_dialogs_toggled ()
 	ARDOUR_UI::config()->set_all_floating_windows_are_dialogs (all_dialogs.get_active());
 }
 
+void
+ThemeManager::on_transients_follow_front_toggled ()
+{
+	ARDOUR_UI::config()->set_transients_follow_front (transients_follow_front.get_active());
+}
+
 void
 ThemeManager::on_waveform_gradient_depth_change ()
 {
@@ -358,6 +370,8 @@ ThemeManager::set_ui_to_state()
 	/* there is no need to block signal handlers, here,
 	 * all elements check if the value has changed and ignore NOOPs 
 	 */
+	all_dialogs.set_active (ARDOUR_UI::config()->get_all_floating_windows_are_dialogs());
+	transients_follow_front.set_active (ARDOUR_UI::config()->get_transients_follow_front());
 	flat_buttons.set_active (ARDOUR_UI::config()->get_flat_buttons());
 	blink_rec_button.set_active (ARDOUR_UI::config()->get_blink_rec_arm());
 	region_color_button.set_active (ARDOUR_UI::config()->get_color_regions_using_track_color());

gtk2_ardour/theme_manager.h

@@ -59,6 +59,7 @@ class ThemeManager : public Gtk::VBox
         void on_waveform_gradient_depth_change ();
         void on_timeline_item_gradient_depth_change ();
 	void on_all_dialogs_toggled ();
+	void on_transients_follow_front_toggled ();
 	void on_icon_set_changed ();
 
   private:
@@ -90,6 +91,7 @@ class ThemeManager : public Gtk::VBox
         Gtk::HScale timeline_item_gradient_depth;
         Gtk::Label timeline_item_gradient_depth_label;
 	Gtk::CheckButton all_dialogs;
+	Gtk::CheckButton transients_follow_front;
 	Gtk::CheckButton gradient_waveforms;
 	Gtk::Label icon_set_label;
 	Gtk::ComboBoxText icon_set_dropdown;

gtk2_ardour/ui_config_vars.h

@@ -25,6 +25,7 @@ UI_CONFIG_VARIABLE (bool, blink_rec_arm, "blink-rec-arm", false)
 UI_CONFIG_VARIABLE (float, waveform_gradient_depth, "waveform-gradient-depth", 0)
 UI_CONFIG_VARIABLE (float, timeline_item_gradient_depth, "timeline-item-gradient-depth", 0.5)
 UI_CONFIG_VARIABLE (bool, all_floating_windows_are_dialogs, "all-floating-windows-are-dialogs", false)
+UI_CONFIG_VARIABLE (bool, transients_follow_front, "transients-follow-front", false)
 UI_CONFIG_VARIABLE (bool, color_regions_using_track_color, "color-regions-using-track-color", false)
 UI_CONFIG_VARIABLE (bool, show_waveform_clipping, "show-waveform-clipping", true)
 UI_CONFIG_VARIABLE (uint32_t, lock_gui_after_seconds, "lock-gui-after-seconds", 0)