diff --git a/src/lib/iter-tree-explorer.hpp b/src/lib/iter-tree-explorer.hpp
index 20e036cc1..25bff8f7c 100644
--- a/src/lib/iter-tree-explorer.hpp
+++ b/src/lib/iter-tree-explorer.hpp
@@ -549,8 +549,6 @@ namespace lib {
             iterNext();         // consume current head element
             if (not isnil(expanded))
               expansions_.push (move(expanded));
-            
-            SRC::expandChildren();
           }
         
         /** diagnostics: current level of nested child expansion */
@@ -593,6 +591,25 @@ namespace lib {
     
     
     
+    template<class SRC>
+    class AutoExpander
+      : public SRC
+      {
+        static_assert(is_StateCore<SRC>::value, "need wrapped state as predecessor in pipeline");
+        
+      public:
+        /** pass through ctor */
+        using SRC::SRC;
+        
+        void
+        iterNext()
+          {
+            SRC::expandChildren();
+          }
+      };
+    
+    
+    
     /**
      * @internal Decorator for TreeExplorer to map a transformation function on all results.
      * The transformation function is invoked on demand, and only once per item to be treated,
@@ -968,8 +985,10 @@ namespace lib {
       auto
       expandAll()
         {
-          UNIMPLEMENTED ("automatically expand all elements");
-          return *this;
+          using ResCore = iter_explorer::AutoExpander<SRC>;
+          using ResIter = typename _DecoratorTraits<ResCore>::SrcIter;
+          
+          return TreeExplorer<ResIter> (ResCore {move(*this)});
         }
       
       
diff --git a/tests/library/iter-tree-explorer-test.cpp b/tests/library/iter-tree-explorer-test.cpp
index 1ab5ef475..96597c831 100644
--- a/tests/library/iter-tree-explorer-test.cpp
+++ b/tests/library/iter-tree-explorer-test.cpp
@@ -807,12 +807,13 @@ namespace test{
       void
       verify_depthFirstExploration()
         {
-          cout << materialise(
+          CHECK (materialise(
                     treeExplore(CountDown{4})
                       .expand([](uint j){ return CountDown{j-1}; })
                       .expandAll()
                       .transform([](int i){ return i*10; })
-                  ) <<endl;
+                    )
+                 == "40-30-20-10-10-20-10-10-30-20-10-10-20-10-10");
           
           
           using std::get;
diff --git a/wiki/thinkPad.ichthyo.mm b/wiki/thinkPad.ichthyo.mm
index afd05fe90..918374823 100644
--- a/wiki/thinkPad.ichthyo.mm
+++ b/wiki/thinkPad.ichthyo.mm
@@ -5757,11 +5757,17 @@
 </html>
 </richcontent>
 <icon BUILTIN="yes"/>
+<node CREATED="1512861383695" ID="ID_837026008" MODIFIED="1512861394833" TEXT="setzt direkt auf drunterliegender State Core auf"/>
+<node CREATED="1512861401133" ID="ID_930964397" MODIFIED="1512861421774" TEXT="ersetzt nur eine der State-Core-Operationen"/>
+<node CREATED="1512861424976" ID="ID_1203553918" MODIFIED="1512861431277" TEXT="sehr einfach, da Typ gleich bleibt"/>
 </node>
-<node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1512844727150" ID="ID_706634236" MODIFIED="1512844732717" TEXT="expandAll">
-<icon BUILTIN="flag-yellow"/>
+<node COLOR="#338800" CREATED="1512844727150" ID="ID_706634236" MODIFIED="1512861467437" TEXT="expandAll">
+<icon BUILTIN="button_ok"/>
 <node CREATED="1512844742788" ID="ID_1270260953" MODIFIED="1512844748479" TEXT="expandChildren verz&#xf6;gert"/>
 <node CREATED="1512844749235" ID="ID_1344028360" MODIFIED="1512844759661" TEXT="ausgel&#xf6;st durch Iteration"/>
+<node CREATED="1512861437832" ID="ID_922141164" MODIFIED="1512861464189" TEXT="iterate() durch expandChildren() ersetzt">
+<icon BUILTIN="forward"/>
+</node>
 </node>
 <node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1512844733549" ID="ID_1055588501" MODIFIED="1512844738184" TEXT="expandLeaf">
 <icon BUILTIN="flag-yellow"/>
@@ -6768,8 +6774,8 @@
 </node>
 <node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1510969031379" ID="ID_1327871737" MODIFIED="1512844596824" TEXT="verify_depthFirstExploration();">
 <icon BUILTIN="pencil"/>
-<node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1512844598906" ID="ID_933777340" MODIFIED="1512844621815" TEXT="expand incl Parent">
-<icon BUILTIN="flag-yellow"/>
+<node COLOR="#338800" CREATED="1512844598906" ID="ID_933777340" MODIFIED="1512861473722" TEXT="expand incl Parent">
+<icon BUILTIN="button_ok"/>
 </node>
 <node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1512844615941" ID="ID_1111018492" MODIFIED="1512844622908" TEXT="auto expand to leafs">
 <icon BUILTIN="flag-yellow"/>