Index: trunk/src/org/openstreetmap/josm/data/osm/TagCollection.java
===================================================================
--- trunk/src/org/openstreetmap/josm/data/osm/TagCollection.java	(revision 4290)
+++ trunk/src/org/openstreetmap/josm/data/osm/TagCollection.java	(revision 4291)
@@ -5,4 +5,5 @@
 
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
@@ -708,6 +709,10 @@
      */
     public String getJoinedValues(String key) {
-        StringBuffer buffer = new StringBuffer();
-        List<String> values = new ArrayList<String>(getValues(key));
+        StringBuilder buffer = new StringBuilder();
+        HashSet<String> valSet = new HashSet<String>();
+        for (String vs : getValues(key)) {
+            valSet.addAll(Arrays.asList(vs.split(";")));
+        }
+        List<String> values = new ArrayList<String>(valSet);
         values.remove("");
         Collections.sort(values);