diff --git a/src/lib/variant.hpp b/src/lib/variant.hpp
index 87621e14b..fe7720055 100644
--- a/src/lib/variant.hpp
+++ b/src/lib/variant.hpp
@@ -341,15 +341,16 @@ namespace lib {
           
           
           
+          static string indicateTypeMismatch (Buffer&);
+          
+          
           static Buff&
           downcast (Buffer& b)
             {
               Buff* buff = dynamic_cast<Buff*> (&b);
               
               if (!buff)
-                throw error::Logic("Variant type mismatch: "
-                                   "the given variant record does not hold "
-                                   "a value of the type requested here"
+                throw error::Logic(indicateTypeMismatch(b)
                                   ,error::LERR_(WRONG_TYPE));
               else
                return *buff;
@@ -550,6 +551,27 @@ namespace lib {
     return util::typedString (this->access());
   }
   
+  /**
+   * error message when accessing the variant content with wrong type assumptions.
+   * @remark while this diagnostics can be crucial for finding bugs, we avoid
+   *  including \ref format-string.hpp, since lib::Variant is used pervasively
+   *  as part of lib::diff::GenNode. Especially in development builds, we observed
+   *  a tangible leverage on executable size. Thus we implement the protection
+   *  against follow-up exceptions explicitly here.
+   */
+  template<typename TYPES>
+  template<typename TY>
+  inline string
+  Variant<TYPES>::Buff<TY>::indicateTypeMismatch(Variant<TYPES>::Buffer& target)
+  {
+    try {
+        return "Variant type mismatch: expected value of type «"
+             + lib::meta::typeStr<TY>()+"», "
+             + "however the given variant record is "
+             + string{target};
+      }
+    catch(...) { return lib::meta::FAILURE_INDICATOR; }
+  }
   
   
 }// namespace lib
diff --git a/src/proc/cmd/meta-cmd.cpp b/src/proc/cmd/meta-cmd.cpp
index 6bed40e8c..25754046f 100644
--- a/src/proc/cmd/meta-cmd.cpp
+++ b/src/proc/cmd/meta-cmd.cpp
@@ -45,6 +45,7 @@
 #include "lib/format-string.hpp"               //////////////////////////////////////////////////////////////TICKET #1099 : include needed temporarily
 //#include "lib/symbol.hpp"
 
+#include <boost/lexical_cast.hpp>
 #include <string>
 
 using lib::hash::LuidH;
@@ -58,6 +59,7 @@ using lib::diff::GenNode;
 //using util::cStr;
 using util::_Fmt;                              //////////////////////////////////////////////////////////////TICKET #1099 : include needed temporarily
 using std::string;
+using boost::lexical_cast;
 
 
 namespace proc {
@@ -211,7 +213,9 @@ COMMAND_DEFINITION (test_meta_markAction)
     def.operation ([](string actionID, string message)
                       {
                         ID errorLogID = gui::interact::Wizard::getErrorLogID();
-                        GuiNotification::facade().mark (errorLogID, GenNode{actionID, message});
+                        GuiNotification::facade().mark (errorLogID
+                                                       ,actionID=="expand"? GenNode{actionID, lexical_cast<bool> (message)}  ///////////FIXME : lexical_cast is not suitable. We need a generic bool parse function!
+                                                                          : GenNode{actionID, message});
                       })
        .captureUndo ([](string actionID, string message) -> string
                       {
diff --git a/wiki/thinkPad.ichthyo.mm b/wiki/thinkPad.ichthyo.mm
index 95c843a50..f5e4089e8 100644
--- a/wiki/thinkPad.ichthyo.mm
+++ b/wiki/thinkPad.ichthyo.mm
@@ -2911,7 +2911,7 @@
 </node>
 </node>
 </node>
-<node COLOR="#338800" CREATED="1533689255174" FOLDED="true" ID="ID_821013695" MODIFIED="1538263469674" TEXT="Aufruf via Notification_Facade">
+<node COLOR="#338800" CREATED="1533689255174" ID="ID_821013695" MODIFIED="1538281518697" TEXT="Aufruf via Notification_Facade">
 <icon BUILTIN="button_ok"/>
 <node COLOR="#338800" CREATED="1537835197558" ID="ID_1477928890" MODIFIED="1538263469674" TEXT="displayInfo">
 <icon BUILTIN="button_ok"/>
@@ -2944,6 +2944,77 @@
 </node>
 <node COLOR="#338800" CREATED="1538239665856" ID="ID_518505874" MODIFIED="1538263469675" TEXT="EXPAND">
 <icon BUILTIN="button_ok"/>
+<node BACKGROUND_COLOR="#fdfdcf" COLOR="#ff0000" CREATED="1538281532767" ID="ID_1335570495" MODIFIED="1538281631433" TEXT="Fehler: mu&#xdf; eigens separate GenNode bauen">
+<richcontent TYPE="NOTE"><html>
+  <head>
+    
+  </head>
+  <body>
+    <p>
+      ...weil der Payload-Typ f&#252;r diesen Aufruf bool ist,
+    </p>
+    <p>
+      und nicht string wie f&#252;r alle anderen state marks
+    </p>
+  </body>
+</html>
+</richcontent>
+<icon BUILTIN="messagebox_warning"/>
+</node>
+<node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1538281608933" ID="ID_584897977" MODIFIED="1538281622963" TEXT="mu&#xdf; bool parsen...">
+<icon BUILTIN="flag-yellow"/>
+<node CREATED="1538281635897" ID="ID_562945035" MODIFIED="1538281651821" TEXT="lexical_cast geht nicht">
+<richcontent TYPE="NOTE"><html>
+  <head>
+    
+  </head>
+  <body>
+    <p>
+      k
+    </p>
+  </body>
+</html>
+</richcontent>
+<icon BUILTIN="button_cancel"/>
+<node CREATED="1538281655774" ID="ID_1847834965" MODIFIED="1538281662977" TEXT="kann nur 1 und 0"/>
+<node BACKGROUND_COLOR="#fdfdcf" COLOR="#ff0000" CREATED="1538281664349" ID="ID_1454517361" MODIFIED="1538281687765" TEXT="interessanter Folgefehler">
+<icon BUILTIN="broken-line"/>
+<node CREATED="1538281691097" ID="ID_1911272932" MODIFIED="1538281757024" TEXT="exception killt ProcDispatcher (das ist OK)">
+<icon BUILTIN="full-1"/>
+</node>
+<node CREATED="1538281708919" ID="ID_1611370738" MODIFIED="1538281759509" TEXT="error state ist gesetzt">
+<icon BUILTIN="full-2"/>
+</node>
+<node CREATED="1538281715646" ID="ID_1541383645" MODIFIED="1538281762796" TEXT="emergency shutdown">
+<icon BUILTIN="full-3"/>
+</node>
+<node CREATED="1538281733340" ID="ID_1326729675" MODIFIED="1538281765434" TEXT="f&#xe4;hrt das GUI runter">
+<icon BUILTIN="full-4"/>
+</node>
+<node CREATED="1538281741419" ID="ID_1964821489" MODIFIED="1538281775756">
+<richcontent TYPE="NODE"><html>
+  <head>
+    
+  </head>
+  <body>
+    <p>
+      ein <b>ZombieCheck</b>&#160;spricht an
+    </p>
+  </body>
+</html>
+</richcontent>
+<icon BUILTIN="full-5"/>
+<node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1538281782245" ID="ID_888818129" MODIFIED="1538281805087" TEXT="welcher...?">
+<icon BUILTIN="help"/>
+</node>
+<node BACKGROUND_COLOR="#fdfdcf" COLOR="#ff0000" CREATED="1538281788117" ID="ID_1747014683" MODIFIED="1538281816152" TEXT="wie konnte das passieren....">
+<icon BUILTIN="help"/>
+<icon BUILTIN="yes"/>
+</node>
+</node>
+</node>
+</node>
+</node>
 </node>
 <node COLOR="#338800" CREATED="1537835859576" ID="ID_968868056" MODIFIED="1538263469675" TEXT="CLEAR_ERR">
 <icon BUILTIN="button_ok"/>