diff --git a/gtk2_ardour/ardour_ui_dialogs.cc b/gtk2_ardour/ardour_ui_dialogs.cc
index f7a61c0891..a8c30c92d8 100644
--- a/gtk2_ardour/ardour_ui_dialogs.cc
+++ b/gtk2_ardour/ardour_ui_dialogs.cc
@@ -116,14 +116,6 @@ ARDOUR_UI::set_session (Session *s)
 
 	transport_ctrl.set_session (s);
 
-	if (big_transport_window) {
-		big_transport_window->set_session (s);
-	}
-
-	if (virtual_keyboard_window) {
-		virtual_keyboard_window->set_session (s);
-	}
-
 	update_path_label ();
 
 	if (!_session) {
@@ -162,10 +154,6 @@ ARDOUR_UI::set_session (Session *s)
 	big_clock->set_session (s);
 	video_timeline->set_session (s);
 	lua_script_window->set_session (s);
-	plugin_manager_ui->set_session (s);
-	plugin_dsp_load_window->set_session (s);
-	dsp_statistics_window->set_session (s);
-	transport_masters_window->set_session (s);
 	rc_option_editor->set_session (s);
 
 	roll_controllable->set_session (s);
@@ -976,7 +964,6 @@ BigTransportWindow*
 ARDOUR_UI::create_big_transport_window ()
 {
 	BigTransportWindow* btw = new BigTransportWindow ();
-	btw->set_session (_session);
 	return btw;
 }
 
@@ -984,7 +971,6 @@ VirtualKeyboardWindow*
 ARDOUR_UI::create_virtual_keyboard_window ()
 {
 	VirtualKeyboardWindow* vkbd = new VirtualKeyboardWindow ();
-	vkbd->set_session (_session);
 	return vkbd;
 }
 
diff --git a/gtk2_ardour/meter_strip.cc b/gtk2_ardour/meter_strip.cc
index f29c99493e..c493a1ee14 100644
--- a/gtk2_ardour/meter_strip.cc
+++ b/gtk2_ardour/meter_strip.cc
@@ -140,7 +140,6 @@ MeterStrip::MeterStrip (Session* sess, boost::shared_ptr<ARDOUR::Route> rt)
 {
 	mtr_vbox.set_spacing (PX_SCALE(2, 2));
 	nfo_vbox.set_spacing (PX_SCALE(2, 2));
-	SessionHandlePtr::set_session (sess);
 	RouteUI::init ();
 	RouteUI::set_route (rt);
 
diff --git a/gtk2_ardour/route_ui.cc b/gtk2_ardour/route_ui.cc
index f6e869d9bb..adf24ad36f 100644
--- a/gtk2_ardour/route_ui.cc
+++ b/gtk2_ardour/route_ui.cc
@@ -142,6 +142,7 @@ RouteUI::RouteUI (ARDOUR::Session* sess)
 	}
 
 	if (sess) {
+		assert (_session);
 		init ();
 	}
 }
diff --git a/gtk2_ardour/window_manager.h b/gtk2_ardour/window_manager.h
index 8c1aeb6ba4..6b80561c07 100644
--- a/gtk2_ardour/window_manager.h
+++ b/gtk2_ardour/window_manager.h
@@ -153,7 +153,12 @@ public:
 		ARDOUR::SessionHandlePtr* sp = session_handle ();
 		if (sp) {
 			sp->set_session (s);
-			dynamic_cast<T*>(_window)->set_session(s);
+		}
+		ARDOUR::SessionHandlePtr* wsp = dynamic_cast<T*>(_window);
+		if (wsp && wsp != sp) {
+			/* can this happen ? */
+			assert (0);
+			wsp->set_session(s);
 		}
 	}
 
@@ -201,7 +206,12 @@ public:
 		ARDOUR::SessionHandlePtr* sp = session_handle ();
 		if (sp) {
 			sp->set_session (s);
-			dynamic_cast<T*>(_window)->set_session(s);
+		}
+		ARDOUR::SessionHandlePtr* wsp = dynamic_cast<T*>(_window);
+		if (wsp && wsp != sp) {
+			/* can this happen ? */
+			assert (0);
+			wsp->set_session(s);
 		}
 	}