diff --git a/src/gui/model/tangible.cpp b/src/gui/model/tangible.cpp
index fb9bcc9b6..04053f770 100644
--- a/src/gui/model/tangible.cpp
+++ b/src/gui/model/tangible.cpp
@@ -189,12 +189,19 @@ namespace model {
   
   /**
    * Perform a command or action, once the execution context has been established.
-   * After binding (and recording) the command arguments, as  supplied with the
+   * After binding (and recording) the command arguments, as supplied with the
    * [record](\ref lib::diff::Rec), the command action is executed right away.
-   * @param instance handle to a command instantiation, to be readied for invocation
+   * @param cmdID indicates the global command definition to be invoked
    * @param arguments suitable tuple of values, to be used to outfit the prototype
+   * @remark may use a previously "opened" instanceID, instead of a global commandID
    */
   void
+  Tangible::invoke (Symbol cmdID, Rec&& arguments)
+  {
+    uiBus_.act (GenNode{string{cmdID}, std::forward<Rec>(arguments)});
+  }
+  /** @deprecated */
+  void
   Tangible::invoke (Cmd const& instance, Rec&& arguments)
   {
     uiBus_.act (instance.triggerMsg (std::forward<Rec>(arguments)));
diff --git a/src/gui/model/tangible.hpp b/src/gui/model/tangible.hpp
index ea44c3543..8a1b6e65f 100644
--- a/src/gui/model/tangible.hpp
+++ b/src/gui/model/tangible.hpp
@@ -135,6 +135,7 @@
 #include "gui/interact/invocation-trail.hpp"
 #include "lib/diff/diff-mutable.hpp"
 #include "lib/idi/entry-id.hpp"
+#include "lib/symbol.hpp"
 
 #include <boost/noncopyable.hpp>
 #include <sigc++/trackable.h>
@@ -146,6 +147,7 @@ namespace gui {
 namespace model {
   
   using std::string;
+  using lib::Symbol;
   
   
   /**
@@ -188,6 +190,9 @@ namespace model {
       void clearMsg();
       void clearErr();
       
+      template<typename...ARGS>
+      void invoke (Symbol cmdID, ARGS&&...);
+      void invoke (Symbol cmdID, Rec&& arguments);
       template<typename...ARGS>
       void invoke (Cmd const& prototype, ARGS&&...);
       void invoke (Cmd const& prototype, Rec&& arguments);
@@ -235,6 +240,18 @@ namespace model {
   /** convenience shortcut to issue a command with several arguments */
   template<typename...ARGS>
   inline void
+  Tangible::invoke (Symbol cmdID, ARGS&&... args)
+  {
+    using GenNodeIL = std::initializer_list<GenNode>;
+    
+    invoke (cmdID,
+            Rec(Rec::TYPE_NIL_SYM
+               ,GenNodeIL{}
+               ,GenNodeIL {std::forward<ARGS> (args)...}));
+  }           // not typed, no attributes, all arguments as children
+  /** @deprecated */
+  template<typename...ARGS>
+  inline void
   Tangible::invoke (Cmd const& prototype, ARGS&&... args)
   {
     using GenNodeIL = std::initializer_list<GenNode>;
diff --git a/src/gui/ui-bus.cpp b/src/gui/ui-bus.cpp
index e78c68cc1..a2a8afadf 100644
--- a/src/gui/ui-bus.cpp
+++ b/src/gui/ui-bus.cpp
@@ -133,8 +133,8 @@ namespace ctrl {
      * @note no information regarding the _origin_ of this command invocation
      *          is captured. If a command needs a _subject_, this has to be
      *          bound as an command argument beforehand.
-     * @see gui::interact::InvocationTrail
      * @see gui::model::Tangible::issueCommand()
+     * @see proc::control::SessionCommand
      */
     void
     BusTerm::act (GenNode const& command)
diff --git a/tests/51-gui-model.tests b/tests/51-gui-model.tests
index e4df756ef..886d79d12 100644
--- a/tests/51-gui-model.tests
+++ b/tests/51-gui-model.tests
@@ -12,7 +12,7 @@ return: 0
 END
 
 
-PLANNED "building block of the UI-Bus" BusTerm_test <<END
+TEST "building block of the UI-Bus" BusTerm_test <<END
 return: 0
 END
 
diff --git a/tests/core/proc/control/session-command-function-test.cpp b/tests/core/proc/control/session-command-function-test.cpp
index 75bc563d2..d2e57d4ad 100644
--- a/tests/core/proc/control/session-command-function-test.cpp
+++ b/tests/core/proc/control/session-command-function-test.cpp
@@ -101,7 +101,6 @@ namespace test    {
   
   using boost::lexical_cast;
   using lib::test::randTime;
-  using gui::interact::InvocationTrail;
   using proc::control::SessionCommand;
   using lib::diff::GenNode;
   using lib::diff::Rec;
@@ -285,19 +284,16 @@ namespace test    {
       
       /** @test invoke a command in the same way as CoreService does
        *        when handling command messages from the UI-Bus
-       *        - use the help of an InvocationTrail, similar to what the
+       *        - build a command message, similar to what the
        *          [generic UI element](\ref gui::model::Tangible) does
-       *        - generate an argument binding message
-       *        - generate a "bang!" message
+       *        - use the contents of this message at the SessionCommand
+       *          facade, similar to what CoreService does
        */
       void
       perform_messageInvocation()
         {
-          // this happens "somewhere" in the UI interaction control framework
-          InvocationTrail invoTrail{Command(COMMAND_I2)};
-          
           // this happens within some tangible UI element (widget / controller)
-          GenNode commandMsg = invoTrail.triggerMsg (Rec {Duration(25,10), Time(500,0), -2});
+          GenNode commandMsg{string(COMMAND_I2), Rec{Duration(25,10), Time(500,0), -2}};
           CHECK (commandMsg.idi.getSym() == string{COMMAND_I2});
           CHECK (not Command::canExec(COMMAND_I2));
           Time prevState = testCommandState;
@@ -364,10 +360,9 @@ namespace test    {
                   for (uint j=0; j<NUM_INVOC_PER_THRED; ++j)
                     {
                       auto cmd = Command(COMMAND_ID).storeDef(cmdID(j));
-                      InvocationTrail invoTrail{cmd};
                       
                       __randomDelay();
-                      sendCommandMessage (invoTrail.triggerMsg (Rec {Duration(7*id_, 2), Time(500,0), -int(j)}));
+                      sendCommandMessage (GenNode{string{cmd.getID()}, Rec{Duration(7*id_, 2), Time(500,0), -int(j)}});
                     }
                 }
               
diff --git a/tests/gui/abstract-tangible-test.cpp b/tests/gui/abstract-tangible-test.cpp
index 8cab8d0f3..221163d6a 100644
--- a/tests/gui/abstract-tangible-test.cpp
+++ b/tests/gui/abstract-tangible-test.cpp
@@ -77,7 +77,6 @@ using lib::diff::GenNode;
 using lib::diff::DataCap;
 using proc::control::Command;
 using proc::control::CommandDef;
-using gui::interact::InvocationTrail;
 using gui::ctrl::MutationMessage;
 
 
@@ -324,12 +323,7 @@ namespace test {
           
           gui::test::Nexus::setCommandHandler (&processCommandInvocation);
           
-          // Usually it's the InvocationStateManager's job to
-          // prepare an "InvocationTrail", which is a prospective
-          // Command invocation about to happen soon.
-          InvocationTrail invoTrail (Command::get (DUMMY_CMD_ID));
-          
-          // the UI element relevant for this command invocation
+          // the UI element to trigger this command invocation
           MockElm mock("uiElm");
           
           int prevState = dummyState;
@@ -340,7 +334,7 @@ namespace test {
           
           
           // message to bind parameter data and finally trigger the command
-          mock.invoke (invoTrail, lib::diff::Rec({concreteParam}));
+          mock.invoke (DUMMY_CMD_ID, lib::diff::Rec({concreteParam}));
           CHECK (dummyState == concreteParam);  // command was indeed invoked
           CHECK (nexusLog.verifyCall("act").arg("«int»|" +toString(concreteParam))
                          .beforeEvent("bind and trigger command \""+DUMMY_CMD_ID));
diff --git a/tests/gui/bus-term-test.cpp b/tests/gui/bus-term-test.cpp
index d75056b20..49b209875 100644
--- a/tests/gui/bus-term-test.cpp
+++ b/tests/gui/bus-term-test.cpp
@@ -29,6 +29,7 @@
 #include "lib/test/test-helper.hpp"
 #include "gui/ctrl/bus-term.hpp"
 #include "gui/ctrl/state-manager.hpp"
+#include "proc/control/command.hpp"
 #include "test/test-nexus.hpp"
 #include "test/mock-elm.hpp"
 #include "lib/idi/entry-id.hpp"
@@ -62,9 +63,7 @@ namespace test {
   using proc::control::LUMIERA_ERROR_UNBOUND_ARGUMENTS;
   using lumiera::error::LUMIERA_ERROR_WRONG_TYPE;
   
-  namespace { // test fixture...
-    
-  }//(End) test fixture
+  using proc::control::Command;
   
   
   
@@ -104,8 +103,7 @@ namespace test {
           replayStateMark();
           verifyNotifications();
           clearStates();
-          pushDiff();
-          destroy();
+//        pushDiff();             ///////////////////////////////////////////////////////////////////////////TICKET #1066
         }
       
       
@@ -188,7 +186,7 @@ namespace test {
         {
           MARK_TEST_FUN
           gui::test::Nexus::startNewLog();
-          auto cmd = gui::test::Nexus::prepareMockCmd<string, TimeSpan, LuidH>();
+          Symbol cmd = gui::test::Nexus::prepareMockCmd<string, TimeSpan, LuidH>();
           
           MockElm mock("uiElm");
           
@@ -197,19 +195,19 @@ namespace test {
           TimeSpan clip (Time(1,2,3), lib::test::randTime());
           LuidH luid;
           
-          // we cannot invoke commands without binding all arguments
-          VERIFY_ERROR (UNBOUND_ARGUMENTS, mock.invoke(cmd) );
+          // we cannot invoke commands without binding required arguments
+          VERIFY_ERROR (WRONG_TYPE, mock.invoke(cmd) );
           
           // proper argument typing is ensured while dispatching the bind message. 
           VERIFY_ERROR (WRONG_TYPE, mock.invoke(cmd, Rec({"lalala"})) );
           
           // command can't be issued, since it's still unbound
-          CHECK (not cmd.canExec());
+          CHECK (not Command::canExec(cmd));
           
           
           mock.invoke (cmd, text, clip, luid);
           
-          CHECK (cmd.canExec());
+          CHECK (Command::canExec(cmd));
           CHECK (gui::test::Nexus::wasBound(cmd, text, clip, luid));
           CHECK (not gui::test::Nexus::wasBound(cmd, "lololo"));
           CHECK (gui::test::Nexus::wasInvoked(cmd));
@@ -220,8 +218,8 @@ namespace test {
           // Mock commands are automatically unique
           auto cmdX = gui::test::Nexus::prepareMockCmd<>();
           auto cmdY = gui::test::Nexus::prepareMockCmd<>();
-          CHECK (cmd.getID() != cmdX.getID());
-          CHECK (cmd.getID() != cmdY.getID());
+          CHECK (cmd != cmdX);
+          CHECK (cmd != cmdY);
           
           CHECK (not gui::test::Nexus::wasInvoked(cmdX));
           CHECK (not gui::test::Nexus::wasInvoked(cmdY));
@@ -508,13 +506,6 @@ namespace test {
         {
           UNIMPLEMENTED ("push a mutation diff towards an interface element");
         }
-      
-      
-      void
-      destroy()
-        {
-          UNIMPLEMENTED ("detach and destroy the test BusTerm");
-        }
     };
   
   
diff --git a/tests/gui/test/test-nexus.hpp b/tests/gui/test/test-nexus.hpp
index a0cd9727f..b58ee4e5e 100644
--- a/tests/gui/test/test-nexus.hpp
+++ b/tests/gui/test/test-nexus.hpp
@@ -101,18 +101,16 @@ namespace test{
       static ctrl::StateManager& getMockStateManager();
       
       
-      using Cmd = interact::InvocationTrail;
+      template<typename...ARGS>
+      static Symbol prepareMockCmd();
+      
+      static bool wasInvoked (Symbol);
       
       template<typename...ARGS>
-      static Cmd prepareMockCmd();
-      
-      static bool wasInvoked (Cmd);
+      static bool wasBound (Symbol, ARGS const& ...args);
       
       template<typename...ARGS>
-      static bool wasBound (Cmd, ARGS const& ...args);
-      
-      template<typename...ARGS>
-      static bool wasInvoked (Cmd, ARGS const& ...args);
+      static bool wasInvoked (Symbol, ARGS const& ...args);
       
     private:
       static void prepareDiagnosticCommandHandler();
@@ -125,19 +123,18 @@ namespace test{
    * which accepts arguments with the denoted types.
    * @note this call installs the command mock into the Proc-Layer
    *       command registry, where it remains in place until shutdown.
-   *       The command uses a synthetic command ID, which is available
-   *       through the returned InvocationTrail. Besides, this call
-   *       also installs a command handler into the Test-Nexus,
+   *       The can be accessed through the generated command ID. Besides,
+   *       this call also installs a command handler into the Test-Nexus,
    *       causing "`act`" messages to be processed and logged.
-   * @return InvocationTrail, the UI-representation of a Proc-Layer command.
-   *         This can be used to trigger command actions on any model::Tangible.
+   * @return the ID of the generated mock command.
    */
   template<typename...ARGS>
-  inline interact::InvocationTrail
+  inline Symbol
   Nexus::prepareMockCmd()
   {
     prepareDiagnosticCommandHandler();
-    return Cmd {PlaceholderCommand<ARGS...>::fabricateNewInstance(getLog())};
+    return PlaceholderCommand<ARGS...>::fabricateNewInstance(getLog())
+                                       .getID();
   }
   
   
@@ -157,12 +154,12 @@ namespace test{
    */
   template<typename...ARGS>
   inline bool
-  Nexus::wasBound (Cmd cmd, ARGS const& ...args)
+  Nexus::wasBound (Symbol cmd, ARGS const& ...args)
   {
     using lib::diff::DataCap;
     
     return getLog()
-            .verifyMatch("TestNexus.+HANDLING Command-Message for .+" +cmd.getID())
+            .verifyMatch("TestNexus.+HANDLING Command-Message for .+" +cmd)
             .beforeCall("bind-command").on("TestNexus")
                                        .arg(string(DataCap(args))...);
   }
@@ -180,14 +177,14 @@ namespace test{
    */
   template<typename...ARGS>
   inline bool
-  Nexus::wasInvoked (Cmd cmd, ARGS const& ...args)
+  Nexus::wasInvoked (Symbol cmd, ARGS const& ...args)
   {
     return getLog()
-            .verifyMatch("TestNexus.+HANDLING Command-Message for .+" +cmd.getID())
-            .beforeCall("exec-command").on("TestNexus").arg(cmd.getID())
+            .verifyMatch("TestNexus.+HANDLING Command-Message for .+" +cmd)
+            .beforeCall("exec-command").on("TestNexus").arg(cmd)
             .beforeCall("exec").on("MockHandlingPattern")
             .beforeCall("operate").arg(util::toString(args)...)
-            .beforeEvent("TestNexus", "SUCCESS handling "+cmd.getID());
+            .beforeEvent("TestNexus", "SUCCESS handling "+cmd);
   }
   
   /**
@@ -195,13 +192,13 @@ namespace test{
    * without matching any concrete arguments
    */
   inline bool
-  Nexus::wasInvoked (Cmd cmd)
+  Nexus::wasInvoked (Symbol cmd)
   {
     return getLog()
-            .verifyMatch("TestNexus.+HANDLING Command-Message for .+" +cmd.getID())
-            .beforeCall("exec-command").on("TestNexus").arg(cmd.getID())
+            .verifyMatch("TestNexus.+HANDLING Command-Message for .+" +cmd)
+            .beforeCall("exec-command").on("TestNexus").arg(cmd)
             .beforeCall("operate")
-            .beforeEvent("TestNexus", "SUCCESS handling "+cmd.getID());
+            .beforeEvent("TestNexus", "SUCCESS handling "+cmd);
   }
   
   
diff --git a/wiki/thinkPad.ichthyo.mm b/wiki/thinkPad.ichthyo.mm
index 22621e228..cc4732577 100644
--- a/wiki/thinkPad.ichthyo.mm
+++ b/wiki/thinkPad.ichthyo.mm
@@ -12384,8 +12384,8 @@
 <node COLOR="#338800" CREATED="1492281610286" ID="ID_1217333147" MODIFIED="1492359761121" TEXT="automatische Instanz-Erzeugung">
 <icon BUILTIN="button_ok"/>
 </node>
-<node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1492281619901" ID="ID_887103826" MODIFIED="1492281874171" TEXT="direkter Aufruf mit CommandDef-ID">
-<icon BUILTIN="flag-yellow"/>
+<node COLOR="#338800" CREATED="1492281619901" ID="ID_887103826" MODIFIED="1492440987297" TEXT="direkter Aufruf mit CommandDef-ID">
+<icon BUILTIN="button_ok"/>
 </node>
 <node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1492281659520" ID="ID_488879231" MODIFIED="1492281875331" TEXT="Argument-Resolver f&#xfc;r Kontext-Zugriff">
 <icon BUILTIN="flag-yellow"/>
@@ -13084,7 +13084,9 @@
 <node COLOR="#338800" CREATED="1492281610286" ID="ID_1542647024" MODIFIED="1492359767992" TEXT="automatische Instanz-Erzeugung">
 <icon BUILTIN="button_ok"/>
 </node>
-<node CREATED="1492281619901" ID="ID_423372741" MODIFIED="1492281631495" TEXT="direkter Aufruf mit CommandDef-ID"/>
+<node COLOR="#338800" CREATED="1492281619901" ID="ID_423372741" MODIFIED="1492440997416" TEXT="direkter Aufruf mit CommandDef-ID">
+<icon BUILTIN="button_ok"/>
+</node>
 <node CREATED="1492281659520" ID="ID_1742758477" MODIFIED="1492281669306" TEXT="Argument-Resolver f&#xfc;r Kontext-Zugriff"/>
 <node CREATED="1492281675557" ID="ID_1809773326" MODIFIED="1492281681224" TEXT="InvocationState mit Callbacks"/>
 </node>