diff --git a/libs/ardour/audioregion.cc b/libs/ardour/audioregion.cc
index ffec0b9b54..38ce0c36a7 100644
--- a/libs/ardour/audioregion.cc
+++ b/libs/ardour/audioregion.cc
@@ -2531,6 +2531,7 @@ AudioRegion::remove_plugin (std::shared_ptr<RegionFxPlugin> fx)
 		send_change (PropertyChange (Properties::region_fx)); // trigger DiskReader overwrite
 	}
 	RegionFxChanged (); /* EMIT SIGNAL */
+	_session.set_dirty ();
 	return true;
 }
 
diff --git a/libs/ardour/region.cc b/libs/ardour/region.cc
index 6f411e3500..9c65b38c18 100644
--- a/libs/ardour/region.cc
+++ b/libs/ardour/region.cc
@@ -2418,7 +2418,11 @@ Region::load_plugin (ARDOUR::PluginType type, std::string const& name)
 bool
 Region::add_plugin (std::shared_ptr<RegionFxPlugin> rfx, std::shared_ptr<RegionFxPlugin> pos)
 {
-	return _add_plugin (rfx, pos, false);
+	bool rv = _add_plugin (rfx, pos, false);
+	if (rv) {
+		_session.set_dirty ();
+	}
+	return rv;
 }
 
 void
@@ -2445,6 +2449,7 @@ Region::reorder_plugins (RegionFxList const& new_order)
 		oiter = _plugins.erase (oiter);
 	}
 	_plugins.insert (oiter, as_it_will_be.begin (), as_it_will_be.end ());
+	_session.set_dirty ();
 }
 
 void