diff --git a/src/lib/iter-chain-search.hpp b/src/lib/iter-chain-search.hpp
index 1d7c19596..b1eec1949 100644
--- a/src/lib/iter-chain-search.hpp
+++ b/src/lib/iter-chain-search.hpp
@@ -213,14 +213,14 @@ namespace iter {
       
       /** drop all search condition frames.
        * @remark the filter chain becomes empty,
-       *         passing through the unaltered
-       *         source sequence
+       *         passing through the reset of the
+       *         source sequence unaltered
        */
       IterChainSearch&&
       clearFilter()
         {
-        //////////////////////////////////////////////////////TODO logically broken. We need also to get rid of the current expansions, while retaining the current position
           stepChain_.clear();
+          _Base::rootCurrent();
           _Base::disableFilter();
           return move(*this);
         }
diff --git a/tests/library/iter-chain-search-test.cpp b/tests/library/iter-chain-search-test.cpp
index 98ede36de..e1688776f 100644
--- a/tests/library/iter-chain-search-test.cpp
+++ b/tests/library/iter-chain-search-test.cpp
@@ -132,7 +132,12 @@ namespace test{
       
       
       
-      /** @test verify the
+      /** @test verify consecutive application of several functors on the underlying filter.
+       * In the general case, each step in the chain is a function working on a copy of the
+       * current filter state. Since each such step configures its own copy of the complete
+       * pipeline, it may reconfigure this filter pipeline in arbitrary ways. After exhausting
+       * the last layer, the evaluation returns to the previous layer, but immediately re-applies
+       * the configuration step on the then next element.
        */
       void
       chainedIteration ()
@@ -141,7 +146,13 @@ namespace test{
       
       
       
-      /** @test verify the
+      /** @test verify a complex search with backtracking.
+       * This becomes relevant when a given search condition can be "too greedy" for the
+       * complete chain to succeed. Most notably this is the case when the search is fundamentally
+       * reconfigured in some steps, e.g. by switching the search orientation. To demonstrate this,
+       * we use a "gear switching" iterator, which allows us to reverse the direction and to search
+       * backwards from the current position. We configure the second condition in the chain such
+       * that it can not succeed when starting from the first match on the first condition
        */
       void
       backtracking ()
diff --git a/wiki/thinkPad.ichthyo.mm b/wiki/thinkPad.ichthyo.mm
index 4ae9bf45f..ea5dc9102 100644
--- a/wiki/thinkPad.ichthyo.mm
+++ b/wiki/thinkPad.ichthyo.mm
@@ -31132,7 +31132,7 @@
 </node>
 </node>
 </node>
-<node COLOR="#338800" CREATED="1536713790340" ID="ID_1436344296" MODIFIED="1536716851593" TEXT="Explorer: rootCurrent()">
+<node COLOR="#338800" CREATED="1536713790340" FOLDED="true" ID="ID_1436344296" MODIFIED="1536717497148" TEXT="Explorer: rootCurrent()">
 <icon BUILTIN="button_ok"/>
 <node CREATED="1536713813792" ID="ID_255912594" MODIFIED="1536713903337" TEXT="Hilfsmittel f&#xfc;r den IterChainSearch">
 <linktarget COLOR="#5c8eb4" DESTINATION="ID_255912594" ENDARROW="Default" ENDINCLINATION="1465;0;" ID="Arrow_ID_1700114612" SOURCE="ID_1097583555" STARTARROW="None" STARTINCLINATION="798;71;"/>
@@ -31686,8 +31686,8 @@
 </node>
 <node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1536018364845" ID="ID_1351452920" MODIFIED="1536329770737" TEXT="Implementierung">
 <icon BUILTIN="pencil"/>
-<node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1536018375244" ID="ID_1906913554" MODIFIED="1536329750864" TEXT="Kern: Explore-Mechanismus">
-<icon BUILTIN="pencil"/>
+<node COLOR="#338800" CREATED="1536018375244" ID="ID_1906913554" MODIFIED="1536717634181" TEXT="Kern: Explore-Mechanismus">
+<icon BUILTIN="button_ok"/>
 <node COLOR="#338800" CREATED="1536018644456" ID="ID_477475522" MODIFIED="1536329729458" TEXT="Signatur der Explore-Funktion festlegen">
 <icon BUILTIN="button_ok"/>
 </node>
@@ -32001,12 +32001,12 @@
 <icon BUILTIN="button_ok"/>
 </node>
 </node>
-<node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1536018923378" ID="ID_1163666446" MODIFIED="1536018929138" TEXT="Pipeline konstruieren">
-<icon BUILTIN="flag-yellow"/>
-<node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1536018931433" ID="ID_1532889609" MODIFIED="1536326576841" TEXT="treeExplorer-Konfiguration">
+<node COLOR="#338800" CREATED="1536018923378" ID="ID_1163666446" MODIFIED="1536717626552" TEXT="Pipeline konstruieren">
+<icon BUILTIN="button_ok"/>
+<node COLOR="#338800" CREATED="1536018931433" ID="ID_1532889609" MODIFIED="1536717484882" TEXT="treeExplorer-Konfiguration">
 <arrowlink COLOR="#65a7b1" DESTINATION="ID_1044555993" ENDARROW="Default" ENDINCLINATION="70;92;" ID="Arrow_ID_575633930" STARTARROW="None" STARTINCLINATION="149;-3;"/>
-<icon BUILTIN="pencil"/>
-<node COLOR="#338800" CREATED="1536353107155" HGAP="33" ID="ID_1163131751" MODIFIED="1536632469176" TEXT="Problem: Basis-Layer" VSHIFT="37">
+<icon BUILTIN="button_ok"/>
+<node COLOR="#338800" CREATED="1536353107155" FOLDED="true" HGAP="33" ID="ID_1163131751" MODIFIED="1536717615755" TEXT="Problem: Basis-Layer" VSHIFT="37">
 <arrowlink COLOR="#4471b4" DESTINATION="ID_942897075" ENDARROW="Default" ENDINCLINATION="37;-79;" ID="Arrow_ID_537236489" STARTARROW="None" STARTINCLINATION="30;44;"/>
 <icon BUILTIN="button_ok"/>
 <node CREATED="1536353117930" ID="ID_625995057" MODIFIED="1536353132265" TEXT="hinzugef&#xfc;gt f&#xfc;r &quot;leeren&quot; Zustand">
@@ -32019,8 +32019,8 @@
 <icon BUILTIN="messagebox_warning"/>
 </node>
 </node>
-<node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1536353280436" ID="ID_967254721" MODIFIED="1536353333302" TEXT="Problem: clearFilter()">
-<icon BUILTIN="flag-yellow"/>
+<node COLOR="#338800" CREATED="1536353280436" FOLDED="true" ID="ID_967254721" MODIFIED="1536717612628" TEXT="Problem: clearFilter()">
+<icon BUILTIN="button_ok"/>
 <node CREATED="1536353286739" ID="ID_1451254899" MODIFIED="1536353295077" TEXT="bauchen wir das &#xfc;berhaupt">
 <icon BUILTIN="help"/>
 <node CREATED="1536353310976" ID="ID_809196267" MODIFIED="1536353322688" TEXT="&quot;Filter komplett abschalten&quot;">
@@ -32030,7 +32030,7 @@
 <icon BUILTIN="idea"/>
 </node>
 </node>
-<node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1536353335500" ID="ID_698525366" MODIFIED="1536358327376" TEXT="mu&#xdf; Stack der partiellen Auswertungen verwerfen">
+<node COLOR="#338800" CREATED="1536353335500" ID="ID_698525366" MODIFIED="1536717475219" TEXT="mu&#xdf; Stack der partiellen Auswertungen verwerfen">
 <richcontent TYPE="NOTE"><html>
   <head>
     
@@ -32045,7 +32045,10 @@
   </body>
 </html></richcontent>
 <arrowlink COLOR="#60a2d5" DESTINATION="ID_33678789" ENDARROW="Default" ENDINCLINATION="315;0;" ID="Arrow_ID_1930258825" STARTARROW="None" STARTINCLINATION="106;0;"/>
-<icon BUILTIN="flag-yellow"/>
+<icon BUILTIN="button_ok"/>
+</node>
+<node CREATED="1536717586774" ID="ID_47823025" MODIFIED="1536717611106" TEXT="mit HIlfsfunktion im TreeExplorer / Expander einfach zu implementieren">
+<icon BUILTIN="idea"/>
 </node>
 </node>
 </node>
@@ -32105,7 +32108,7 @@
 </node>
 <node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1536357878006" ID="ID_1225195123" MODIFIED="1536358257081" TEXT="Aufr&#xe4;umen und nachr&#xfc;sten">
 <icon BUILTIN="pencil"/>
-<node COLOR="#338800" CREATED="1536357891412" ID="ID_942897075" MODIFIED="1536632466623" TEXT="den Basis-Layer eliminieren">
+<node COLOR="#338800" CREATED="1536357891412" FOLDED="true" ID="ID_942897075" MODIFIED="1536717539462" TEXT="den Basis-Layer eliminieren">
 <linktarget COLOR="#4471b4" DESTINATION="ID_942897075" ENDARROW="Default" ENDINCLINATION="37;-79;" ID="Arrow_ID_537236489" SOURCE="ID_1163131751" STARTARROW="None" STARTINCLINATION="30;44;"/>
 <icon BUILTIN="button_ok"/>
 <node COLOR="#338800" CREATED="1536357900635" ID="ID_646733499" MODIFIED="1536533192790" TEXT="brauche einen &quot;leer&quot;-Status im Filter">
@@ -32140,15 +32143,15 @@
 </node>
 </node>
 </node>
-<node COLOR="#338800" CREATED="1536539286897" ID="ID_1288939799" MODIFIED="1536631289616" TEXT="overconstrained triggert Assertion">
+<node COLOR="#338800" CREATED="1536539286897" FOLDED="true" ID="ID_1288939799" MODIFIED="1536717548060" TEXT="overconstrained triggert Assertion">
 <linktarget COLOR="#c5789c" DESTINATION="ID_1288939799" ENDARROW="Default" ENDINCLINATION="99;3;" ID="Arrow_ID_1528021143" SOURCE="ID_487266350" STARTARROW="None" STARTINCLINATION="-35;27;"/>
 <icon BUILTIN="button_ok"/>
 <node CREATED="1536631251921" HGAP="51" ID="ID_588077559" MODIFIED="1536631280009" TEXT="sollte stattdessen leer werden" VSHIFT="23">
 <icon BUILTIN="yes"/>
 </node>
 </node>
-<node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1536357967826" ID="ID_634133289" MODIFIED="1536358245365" TEXT="clearFilter()">
-<icon BUILTIN="flag-yellow"/>
+<node COLOR="#338800" CREATED="1536357967826" FOLDED="true" ID="ID_634133289" MODIFIED="1536717583623" TEXT="clearFilter()">
+<icon BUILTIN="button_ok"/>
 <node CREATED="1536357973769" ID="ID_33678789" MODIFIED="1536358316984" TEXT="brauche Unterst&#xfc;tzung vom Expander">
 <linktarget COLOR="#60a2d5" DESTINATION="ID_33678789" ENDARROW="Default" ENDINCLINATION="315;0;" ID="Arrow_ID_1930258825" SOURCE="ID_698525366" STARTARROW="None" STARTINCLINATION="106;0;"/>
 <icon BUILTIN="messagebox_warning"/>
@@ -32200,8 +32203,8 @@
 <icon BUILTIN="idea"/>
 </node>
 </node>
-<node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1536018539621" ID="ID_1857591081" MODIFIED="1536329779734" TEXT="simpleSearch()">
-<icon BUILTIN="pencil"/>
+<node COLOR="#338800" CREATED="1536018539621" ID="ID_1857591081" MODIFIED="1536717648741" TEXT="simpleSearch()">
+<icon BUILTIN="button_ok"/>
 </node>
 <node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1536018544936" ID="ID_1750921303" MODIFIED="1536018557580" TEXT="chainedIteration()">
 <icon BUILTIN="flag-yellow"/>