diff --git a/src/gui/ctrl/mutation-message.hpp b/src/gui/ctrl/mutation-message.hpp
index e83b14a9c..6680acc7f 100644
--- a/src/gui/ctrl/mutation-message.hpp
+++ b/src/gui/ctrl/mutation-message.hpp
@@ -109,7 +109,7 @@ namespace ctrl{
      * @note this is a pragmatic guess, based on the actual usage pattern within Lumiera.
      *       This determines the size of the inline buffer within MutationMessage.
      *       You'll get an static assertion failure when creating a MutationMessage
-     *       from a concrete diff representation requiring more size...
+     *       from a concrete diff representation requires more storage space...
      */
     enum { SIZE_OF_DIFF_REPRESENTATION = sizeof(std::vector<string>)
                                        + sizeof(size_t)
diff --git a/src/gui/interact/invocation-trail.hpp b/src/gui/interact/invocation-trail.hpp
index f9fef5730..e7a4b9f7f 100644
--- a/src/gui/interact/invocation-trail.hpp
+++ b/src/gui/interact/invocation-trail.hpp
@@ -33,7 +33,7 @@
  ** actual values is tracked by an [InvocationTrail] handle. When
  ** ready, finally this handle can be issued on any [BusTerm].
  ** 
- ** @todo as of 11/2015 this is complete WIP-WIP-WIP
+ ** @todo as of 11/2015 this is more of a concept draft
  ** 
  ** @see ////TODO_test usage example
  ** 
@@ -86,6 +86,7 @@ namespace interact {
        *    exist somewhere in the system and IDs to be sent over the bus, without the certainty
        *    of a real invocation site and a matching command operation to exist somewhere else
        *    within the system.
+       * @todo do we need an alternative ctor based on plain command-ID?                 ///////////////////////////TICKET #1060 : create a dedicated command-ID type?
        */
       InvocationTrail(proc::control::Command prototype)
         : cmdID_(prototype.getID())
diff --git a/tests/core/proc/control/session-command-function-test.cpp b/tests/core/proc/control/session-command-function-test.cpp
index e7f56f8ef..1c76555ad 100644
--- a/tests/core/proc/control/session-command-function-test.cpp
+++ b/tests/core/proc/control/session-command-function-test.cpp
@@ -30,9 +30,7 @@ extern "C" {
 #include "proc/control/proc-dispatcher.hpp"
 #include "proc/control/command-def.hpp"
 #include "gui/ctrl/command-handler.hpp"
-#include "proc/asset/meta/time-grid.hpp"
-#include "lib/time/timequant.hpp"
-#include "lib/time/timecode.hpp"
+#include "gui/interact/invocation-trail.hpp"
 #include "lib/format-obj.hpp"
 #include "lib/format-cout.hpp" //////////TODO
 #include "lib/symbol.hpp"
@@ -50,7 +48,9 @@ namespace test    {
 //  using std::function;
 //  using std::rand;
   using lib::test::randTime;
+  using gui::interact::InvocationTrail;
   using gui::ctrl::CommandHandler;
+  using lib::diff::GenNode;
   using lib::diff::Rec;
   using lib::time::Time;
   using lib::time::TimeVar;
@@ -86,7 +86,7 @@ namespace test    {
     void
     undoIt (Duration, Offset, int, Time oldState)
     {
-//    dummyState = oldState;
+      testCommandState = oldState;
     }
     
     
@@ -200,7 +200,7 @@ namespace test    {
           SessionCommand::facade().invoke(cmdID);
           
           __DELAY__
-          CHECK (testCommandState - prevState == Time(0, 1));
+          CHECK (testCommandState - prevState == Time(0, 1));           // execution added 1500ms -1*500ms == 1sec
         }
       
       
@@ -214,7 +214,29 @@ namespace test    {
       void
       perform_messageInvocation()
         {
-          UNIMPLEMENTED ("invoke via message");
+          // this happens "somewhere" in the UI interaction control framework
+          InvocationTrail invoTrail{Command(COMMAND_ID)};
+          
+          // this happens within some tangible UI element (widget / controller)
+          GenNode argumentBindingMessage = invoTrail.bindMsg (Rec{Duration(25,10), Time(500,0), -2});
+          GenNode commandTriggerMessage  = invoTrail.bangMsg ();
+          CHECK (argumentBindingMessage.idi == commandTriggerMessage.idi);
+          
+          // this happens, when CoreService receives command messages from UI-Bus
+          CommandHandler handler1{argumentBindingMessage};
+          argumentBindingMessage.data.accept(handler1);                 // handler is a visitor for the message payload
+          
+          CHECK (Command::canExec(COMMAND_ID));
+          CHECK (not Command::canUndo(COMMAND_ID));
+          Time prevState = testCommandState;
+          
+          // now handling the message to trigger execution
+          CommandHandler handler2{commandTriggerMessage};
+          commandTriggerMessage.data.accept(handler2);
+          
+          __DELAY__
+          CHECK (Command::canUndo(COMMAND_ID));
+          CHECK (testCommandState - prevState == Time(500, 1));         // execution added 2500ms -2*500ms == 1.5sec
         }