diff --git a/src/lib/element-tracker.hpp b/src/lib/element-tracker.hpp
index 2a0515d08..2b72c0f1d 100644
--- a/src/lib/element-tracker.hpp
+++ b/src/lib/element-tracker.hpp
@@ -68,6 +68,7 @@ namespace lib {
   
   using lumiera::P;
   using std::tr1::function;
+  using util::isSameObject;
   
   /**
    * Registry for tracking object instances.
@@ -229,6 +230,13 @@ namespace lib {
           getRegistry = RegistryLink();  // empty accessor function
         }
       
+      static bool
+      is_attached_to (Registry const& someRegistry)
+        {
+          return bool(getRegistry)
+              && isSameObject (someRegistry, getRegistry());
+        }
+      
     protected:
       static RegistryLink getRegistry;
     };
diff --git a/src/proc/asset/struct.cpp b/src/proc/asset/struct.cpp
index 7ed42b2f6..fbfaec89c 100644
--- a/src/proc/asset/struct.cpp
+++ b/src/proc/asset/struct.cpp
@@ -82,7 +82,7 @@ namespace asset {
    *  instances and immediately creates a new one.
    * @param nameID (optional) an ID to use; if omitted an ID
    *        will be default created, based on the kind of Asset.
-   * @throw error::Invalid in case of ID clash with an existing Asset        
+   * @throw error::Invalid in case of ID clash with an existing Asset
    * @return  an Struct smart ptr linked to the internally registered smart ptr
    *        created as a side effect of calling the concrete Struct subclass ctor.
    */
diff --git a/src/proc/mobject/session/session-interface-modules.hpp b/src/proc/mobject/session/session-interface-modules.hpp
index 46878a272..437bc5663 100644
--- a/src/proc/mobject/session/session-interface-modules.hpp
+++ b/src/proc/mobject/session/session-interface-modules.hpp
@@ -120,9 +120,12 @@ namespace session {
   inline
   SessionInterfaceModules::~SessionInterfaceModules()
   {
-    asset::Sequence::deactivateRegistryLink();
-    asset::Timeline::deactivateRegistryLink();
-  }
+    if (asset::Sequence::is_attached_to (sequenceRegistry_))
+      asset::Sequence::deactivateRegistryLink();
+    
+    if (asset::Timeline::is_attached_to (timelineRegistry_))  // as session dtor is invoked automatically (smart-ptr),
+      asset::Timeline::deactivateRegistryLink();             //  another new session might already have grabbed
+  }                                                         //   the Timeline / Sequence registration service.
   
   
   
diff --git a/tests/43session.tests b/tests/43session.tests
index 40a81d269..85242cd65 100644
--- a/tests/43session.tests
+++ b/tests/43session.tests
@@ -32,7 +32,7 @@ out: DummyMO\.[0-9]{3}
 END
 
 
-PLANNED "SessionElementTracker_test" SessionElementTracker_test <<END
+TEST "SessionElementTracker_test" SessionElementTracker_test <<END
 END
 
 
diff --git a/tests/components/proc/mobject/session/session-element-tracker-test.cpp b/tests/components/proc/mobject/session/session-element-tracker-test.cpp
index ca1d9c648..c7e90b96b 100644
--- a/tests/components/proc/mobject/session/session-element-tracker-test.cpp
+++ b/tests/components/proc/mobject/session/session-element-tracker-test.cpp
@@ -181,13 +181,13 @@ namespace test    {
           uint num_timelines = sess->timelines.size();
           CHECK (0 < num_timelines);
           
-          PTimeline specialTimeline (asset::Struct::retrieve (Query<Timeline> ("id(testical)")));
+          PTimeline specialTimeline (asset::Struct::retrieve.newInstance<Timeline> ("testical"));
           CHECK (specialTimeline);
           CHECK (num_timelines + 1 == sess->timelines.size());
           CHECK (specialTimeline == sess->timelines[num_timelines]);    // got appended at the end of the tracking table
-          CHECK (specialTimeline.use_count() == 4);                     // we, the AssetManager and the session   /////TODO plus one for fake-configrules
+          CHECK (specialTimeline.use_count() == 3);                     // we, the AssetManager and the session
           
-          PTimeline anotherTimeline (asset::Struct::retrieve (Query<Timeline> ()));
+          PTimeline anotherTimeline (asset::Struct::retrieve.newInstance<Timeline>());
           CHECK (num_timelines + 2 == sess->timelines.size());
           CHECK (specialTimeline == sess->timelines[num_timelines]);
           CHECK (anotherTimeline == sess->timelines[num_timelines+1]);  // new one got appended at the end
@@ -212,7 +212,7 @@ namespace test    {
         {
           REQUIRE (1 < aTimeline_in_session.use_count(), "test object should still be attached to session");
           Session::current.reset();
-          aTimeline_in_session->detach();           // should be a no-op and not cause any invalid access
+          aTimeline_in_session->detach();              // should be a no-op and not cause any invalid access
         }
     };