ENH: only update meshSubset on topo change

src/dynamicMesh/meshSubsetHelper/meshSubsetHelper.C

@@ -92,7 +92,7 @@ Foam::polyMesh::readUpdateState Foam::meshSubsetHelper::readUpdate()
 {
     polyMesh::readUpdateState meshState = baseMesh_.readUpdate();
 
-    if (meshState != polyMesh::UNCHANGED)
+    if (meshState == polyMesh::TOPO_CHANGE || polyMesh::TOPO_PATCH_CHANGE)
     {
         correct(true);
     }

src/dynamicMesh/meshSubsetHelper/meshSubsetHelper.H

@@ -146,7 +146,7 @@ public:
         //- Update mesh subset
         void correct(bool verbose = false);
 
-        //- Read mesh
+        //- Read mesh. Correct on topo-change
         polyMesh::readUpdateState readUpdate();