diff --git a/gtk2_ardour/session_dialog.cc b/gtk2_ardour/session_dialog.cc
index 003c16ae52..762cdd5271 100644
--- a/gtk2_ardour/session_dialog.cc
+++ b/gtk2_ardour/session_dialog.cc
@@ -166,13 +166,11 @@ SessionDialog::SessionDialog (DialogTab initial_tab, const std::string& session_
 	existing_session_chooser.show_all();
 
 	_tabs.show_all();
-	_tabs.set_current_page(0);
 
 	cancel_button = add_button ((cancel_not_quit ? Stock::CANCEL : Stock::QUIT), RESPONSE_CANCEL);
 
 	open_button = add_button (Stock::OPEN, RESPONSE_ACCEPT);
 	open_button->signal_button_press_event().connect (sigc::mem_fun (*this, &SessionDialog::open_button_pressed), false);
-	open_button->set_sensitive (false);
 
 	if (!template_name.empty()) {
 		load_template_override = template_name;
@@ -204,9 +202,9 @@ SessionDialog::SessionDialog (DialogTab initial_tab, const std::string& session_
 	}
 
 	_tabs.signal_switch_page().connect (sigc::mem_fun (*this, &SessionDialog::tab_page_switched));
+	_tabs.set_current_page(3);  //this will enforce a page-change, so correct widgets get sensitized
 	if (initial_tab==New) {
 		_tabs.set_current_page(0);
-		new_button.set_active_state (Gtkmm2ext::ExplicitActive);
 	} else if (initial_tab==Open) {
 		_tabs.set_current_page(2);
 	} else {
@@ -227,6 +225,14 @@ SessionDialog::tab_page_switched(GtkNotebookPage*, guint page_number)
 	recent_button.set_active_state (  page_number==1 ? Gtkmm2ext::ExplicitActive : Gtkmm2ext::Off);
 	existing_button.set_active_state (page_number==2 ? Gtkmm2ext::ExplicitActive : Gtkmm2ext::Off);
 	prefs_button.set_active_state (   page_number==3 ? Gtkmm2ext::ExplicitActive : Gtkmm2ext::Off);
+
+	//check the status of each tab and sensitize the 'open' button appropriately
+	open_button->set_sensitive(false);
+	switch (page_number) {
+		case 0: new_name_changed(); break;
+		case 1: recent_session_row_selected(); break;
+		case 2: existing_file_selected(); break;
+	}
 }
 
 uint32_t
@@ -480,6 +486,11 @@ SessionDialog::setup_existing_box ()
 void
 SessionDialog::existing_file_selected ()
 {
+	if (_tabs.get_current_page()!=2) {
+		//gtk filechooser is threaded; don't allow it to mess with open_button sensitivity when it's not actually visible
+		return;
+	}
+
 	open_button->set_sensitive(false);
 
 	float sr;
@@ -534,8 +545,6 @@ SessionDialog::new_button_pressed (GdkEventButton*)
 {
 	_tabs.set_current_page(0);
 
-	new_name_changed();  //checks for a valid name and (maybe) sensitizes the button
-
 	return true;
 }
 
@@ -544,8 +553,6 @@ SessionDialog::recent_button_pressed (GdkEventButton*)
 {
 	_tabs.set_current_page(1);
 
-	recent_session_row_selected();  //checks for a selection and (maybe) sensitizes the open button
-
 	return true;
 }
 
@@ -554,8 +561,6 @@ SessionDialog::existing_button_pressed (GdkEventButton*)
 {
 	_tabs.set_current_page(2);
 
-	existing_file_selected();  //checks for a selection and (maybe) sensitizes the open button
-
 	return true;
 }