Index: /trunk/src/org/openstreetmap/josm/gui/dialogs/relation/MemberTable.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/gui/dialogs/relation/MemberTable.java	(revision 10682)
+++ /trunk/src/org/openstreetmap/josm/gui/dialogs/relation/MemberTable.java	(revision 10683)
@@ -7,8 +7,8 @@
 import java.awt.GraphicsEnvironment;
 import java.awt.event.ActionEvent;
-import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
-import java.util.List;
+import java.util.HashSet;
+import java.util.Set;
 
 import javax.swing.AbstractAction;
@@ -110,5 +110,5 @@
         if (Main.isDisplayingMapView()) {
             Collection<RelationMember> sel = getMemberTableModel().getSelectedMembers();
-            final List<OsmPrimitive> toHighlight = new ArrayList<>();
+            final Set<OsmPrimitive> toHighlight = new HashSet<>();
             for (RelationMember r: sel) {
                 if (r.getMember().isUsable()) {