diff --git a/src/common/query/mockconfigrules.cpp b/src/common/query/mockconfigrules.cpp
index ddc7bd57a..c8b9f774b 100644
--- a/src/common/query/mockconfigrules.cpp
+++ b/src/common/query/mockconfigrules.cpp
@@ -100,7 +100,7 @@ namespace lumiera
       item<cPP> (answer_, "stream(default)")  = item<cPP> (answer_,"stream(video)"); // set up a default stream
       
       answer_->insert (entry_Struct<Pipe> ("pipe(master), stream(video)"));
-      item<Pipe> (answer_, "default(P)") = item<Pipe>(answer_,"pipe(master), stream(video)");
+      item<Pipe> (answer_, "") = item<Pipe>(answer_,"pipe(master), stream(video)");//   use as default
     }
     
     
@@ -122,7 +122,7 @@ namespace lumiera
     }
     /** special case: create a new pipe for a specific stream ID */
     bool 
-    MockTable::fabricate_new_Pipe_for_stream (Query<Pipe>& q, string const& streamID)
+    MockTable::fabricate_just_new_Pipe (Query<Pipe>& q )
     {
       typedef WrapReturn<Pipe>::Wrapper Ptr;
       
@@ -147,6 +147,7 @@ namespace lumiera
     bool 
     MockTable::set_new_mock_solution (Query<TY>& q, typename WrapReturn<TY>::Wrapper& obj)
     {
+      answer_->erase (q.asKey());
       answer_->insert (entry<TY> (q, obj));
       return true;
     }
diff --git a/src/common/query/mockconfigrules.hpp b/src/common/query/mockconfigrules.hpp
index dba328754..f5bea3264 100644
--- a/src/common/query/mockconfigrules.hpp
+++ b/src/common/query/mockconfigrules.hpp
@@ -111,7 +111,7 @@ namespace lumiera
         template<class TY> 
         bool detect_case (typename WrapReturn<TY>::Wrapper&, Query<TY>& q);
         bool fabricate_matching_new_Pipe (Query<Pipe>& q, string const& pipeID, string const& streamID);
-        bool fabricate_new_Pipe_for_stream (Query<Pipe>& q, string const& streamID);
+        bool fabricate_just_new_Pipe (Query<Pipe>& q);
         bool fabricate_ProcPatt_on_demand (Query<const ProcPatt>& q, string const& streamID);
         
         template<class TY>
@@ -195,8 +195,8 @@ namespace lumiera
       if (!isnil(pipeID) && !isnil(streamID))
         return fabricate_matching_new_Pipe (q, pipeID, streamID);
 
-      if (!candidate && !isnil(streamID))
-        return fabricate_new_Pipe_for_stream (q, streamID);
+      if (!candidate && (!isnil(streamID) || !isnil(pipeID)))
+        return fabricate_just_new_Pipe (q);
       
       q.clear();
       return false;
diff --git a/tests/53session.tests b/tests/53session.tests
index 64946fcf2..887cbdf4c 100644
--- a/tests/53session.tests
+++ b/tests/53session.tests
@@ -6,7 +6,8 @@ PLANNED "AddClip_test" AddClip_test <<END
 END
 
 
-PLANNED "DefsManager_test" DefsManager_test <<END
+TEST "DefsManager_test" DefsManager_test <<END
+return: 0
 END
 
 
diff --git a/tests/components/proc/mobject/session/defsmanagertest.cpp b/tests/components/proc/mobject/session/defsmanagertest.cpp
index 1e66a0553..5f5ed686e 100644
--- a/tests/components/proc/mobject/session/defsmanagertest.cpp
+++ b/tests/components/proc/mobject/session/defsmanagertest.cpp
@@ -27,6 +27,7 @@
 #include "proc/asset.hpp"
 #include "proc/asset/pipe.hpp"
 #include "common/query.hpp"
+#include "common/configrules.hpp"   ///////TODO just temp
 #include "proc/assetmanager.hpp"
 #include "proc/mobject/session.hpp"
 
@@ -46,6 +47,9 @@ namespace asset
     using lumiera::Query;
     using lumiera::query::normalizeID;
     
+    using lumiera::ConfigRules;               ////TODO just temp
+    using lumiera::query::QueryHandler;      ////TODO just temp
+    
     
     /** shortcut: run just a query
      *  without creating new instances
@@ -60,7 +64,7 @@ namespace asset
     
     
     /***********************************************************************
-     * @test basic behaviour of the defaults manager.
+     * @test basic behaviour of the defaults manager ("the big picture")
      *       <ol><li>retrieving a "default" object repeatedly</li>
      *           <li>retrieving a more constrained "default" object</li>
      *           <li>failure registers a new "default"</li>
@@ -101,7 +105,7 @@ namespace asset
             ASSERT (pipe2 == pipe1);
             pipe2 = asset::Struct::create (Query<Pipe> ());
             ASSERT (pipe2 == pipe1);
-            pipe2 = asset::Struct::create (Query<Pipe> ("default(X)"));
+            pipe2 = asset::Struct::create (Query<Pipe> ("default(P)"));
             ASSERT (pipe2 == pipe1);
           }
         
@@ -144,12 +148,30 @@ namespace asset
           }
         
         
+        /** verify the defaults manager holds only weak refs,
+         *  so if an object goes out of scope, any defaults entries
+         *  are purged silently
+         */
         void verifyRemoval (string pID)
           { 
             Query<Pipe> query_for_pID ("pipe("+pID+")");
             size_t hash;
               {
                 PPipe pipe1 = Session::current->defaults (query_for_pID);
+//
+// this is fine but doesn't work as long as there is another entry in the mock table...
+// ...for now we use hack to overwrite the reference in the mock table                
+//
+                ASSERT (3 == pipe1.use_count());  // that's the problem; it should be 2
+                
+                QueryHandler<Pipe>& typeHandler = ConfigRules::instance();  
+                PPipe pipe2 = asset::Struct::create (pID, "quatsch");
+
+                typeHandler.resolve (pipe2, query_for_pID); // in the mock impl this has the side effect
+                ASSERT (pipe2);                            //  of replacing the mock entry
+                ////////////////////////////////////////////   so from now on the test works as intended....                
+                
+                ASSERT (2 == pipe1.use_count());          
                 hash = pipe1->getID();
               }
              // now AssetManager should hold the only ref