Index: trunk/src/org/openstreetmap/josm/data/conflict/ConflictCollection.java
===================================================================
--- trunk/src/org/openstreetmap/josm/data/conflict/ConflictCollection.java	(revision 15294)
+++ trunk/src/org/openstreetmap/josm/data/conflict/ConflictCollection.java	(revision 15295)
@@ -291,5 +291,7 @@
     public void add(ConflictCollection other) {
         for (Conflict<?> c : other) {
-            add(c);
+            if (!hasConflict(c)) {
+                add(c);
+            }
         }
     }