Index: trunk/src/org/openstreetmap/josm/data/validation/tests/MultipolygonTest.java
===================================================================
--- trunk/src/org/openstreetmap/josm/data/validation/tests/MultipolygonTest.java	(revision 17220)
+++ trunk/src/org/openstreetmap/josm/data/validation/tests/MultipolygonTest.java	(revision 17221)
@@ -19,5 +19,5 @@
 import java.util.stream.IntStream;
 
-import org.openstreetmap.josm.command.ChangeCommand;
+import org.openstreetmap.josm.command.ChangeMembersCommand;
 import org.openstreetmap.josm.command.Command;
 import org.openstreetmap.josm.data.coor.EastNorth;
@@ -743,5 +743,4 @@
             if (primitives.size() >= 2 && primitives.get(0) instanceof Relation) {
                 Relation oldRel = (Relation) primitives.get(0);
-                Relation newRel = new Relation(oldRel);
                 List<OsmPrimitive> repeatedPrims = primitives.subList(1, primitives.size());
                 List<RelationMember> oldMembers = oldRel.getMembers();
@@ -752,6 +751,5 @@
                 for (RelationMember rm : oldMembers) {
                     if (toRemove.contains(rm.getMember())) {
-                        if (!found.contains(rm.getMember())) {
-                            found.add(rm.getMember());
+                        if (found.add(rm.getMember())) {
                             newMembers.add(rm);
                         }
@@ -760,6 +758,5 @@
                     }
                 }
-                newRel.setMembers(newMembers);
-                return new ChangeCommand(oldRel, newRel);
+                return new ChangeMembersCommand(oldRel, newMembers);
             }
         }