diff --git a/defaults/yacy.init b/defaults/yacy.init
index 9dfb51027..d79b2684c 100644
--- a/defaults/yacy.init
+++ b/defaults/yacy.init
@@ -825,6 +825,7 @@ search.result.show.tags = false
 # can be temporary different if search string is given with differen navigation values
 # assigning no value(s) means that no navigation is shown
 search.navigation=location,hosts,authors,namespace,topics,filetype,protocol,language
+#search.navigation=location,hosts,authors,namespace,topics,filetype,protocol,language,collections
 
 # search result verification and snippet fetch caching rules
 # each search result can be verified byloading the link from the web
diff --git a/htroot/ConfigPortal.java b/htroot/ConfigPortal.java
index f0dd5888e..61a335d30 100644
--- a/htroot/ConfigPortal.java
+++ b/htroot/ConfigPortal.java
@@ -170,6 +170,7 @@ public class ConfigPortal {
         
         prop.put("search.navigation.hosts", sb.getConfig("search.navigation", "").indexOf("hosts",0) >= 0 ? 1 : 0);
         prop.put("search.navigation.authors", sb.getConfig("search.navigation", "").indexOf("authors",0) >= 0 ? 1 : 0);
+        prop.put("search.navigation.collections", sb.getConfig("search.navigation", "").indexOf("collections",0) >= 0 ? 1 : 0);
         prop.put("search.navigation.namespace", sb.getConfig("search.navigation", "").indexOf("namespace",0) >= 0 ? 1 : 0);
         prop.put("search.navigation.topics", sb.getConfig("search.navigation", "").indexOf("topics",0) >= 0 ? 1 : 0);
 
diff --git a/htroot/ConfigSearchPage_p.html b/htroot/ConfigSearchPage_p.html
index bbd6990e8..07117f677 100644
--- a/htroot/ConfigSearchPage_p.html
+++ b/htroot/ConfigSearchPage_p.html
@@ -125,13 +125,19 @@
                         <td><ul class="nav nav-sidebar menugroup" id="sidebarLanguages" style="padding-left:15px; padding-right:10px;">
                           <li><h3>Language</h3></li>
                           </ul></td>
-                      </tr>                  
+                      </tr>
                       <tr>
                         <td><input type="checkbox" name="search.navigation.authors" value="true" #(search.navigation.authors)#::checked="checked" #(/search.navigation.authors)# /></td>
                         <td><ul class="nav nav-sidebar menugroup" id="sidebarAuthors" style="padding-left:15px; padding-right:10px;">
                           <li><h3>Author</h3></li>
                           </ul></td>
                       </tr>
+                      <tr>
+                        <td><input type="checkbox" name="search.navigation.collections" value="true" #(search.navigation.collections)#::checked="checked" #(/search.navigation.collections)# /></td>
+                        <td><ul class="nav nav-sidebar menugroup" id="sidebarCollections" style="padding-left:15px; padding-right:10px;">
+                          <li><h3>Collection</h3></li>
+                          </ul></td>
+                      </tr>
                       <tr>
                         <td></td>
                         <td><ul class="nav nav-sidebar menugroup" id="vocabulary" style="padding-left:15px; padding-right:10px;">
diff --git a/htroot/ConfigSearchPage_p.java b/htroot/ConfigSearchPage_p.java
index f1714ee7c..5bbaf4748 100644
--- a/htroot/ConfigSearchPage_p.java
+++ b/htroot/ConfigSearchPage_p.java
@@ -85,6 +85,7 @@ public class ConfigSearchPage_p {
                 if (post.getBoolean("search.navigation.hosts")) nav += "hosts,";
                 if (post.getBoolean("search.navigation.language")) nav += "language,";
                 if (post.getBoolean("search.navigation.authors")) nav += "authors,";
+                if (post.getBoolean("search.navigation.collections")) nav += "collections,";
                 if (post.getBoolean("search.navigation.namespace")) nav += "namespace,";
                 if (post.getBoolean("search.navigation.topics")) nav += "topics,";
                 if (nav.endsWith(",")) nav = nav.substring(0, nav.length() - 1);
@@ -162,6 +163,7 @@ public class ConfigSearchPage_p {
         prop.put("search.navigation.hosts", sb.getConfig("search.navigation", "").indexOf("hosts",0) >= 0 ? 1 : 0);
         prop.put("search.navigation.language", sb.getConfig("search.navigation", "").indexOf("language",0) >= 0 ? 1 : 0);
         prop.put("search.navigation.authors", sb.getConfig("search.navigation", "").indexOf("authors",0) >= 0 ? 1 : 0);
+        prop.put("search.navigation.collections", sb.getConfig("search.navigation", "").indexOf("collections",0) >= 0 ? 1 : 0);
         prop.put("search.navigation.namespace", sb.getConfig("search.navigation", "").indexOf("namespace",0) >= 0 ? 1 : 0);
         prop.put("search.navigation.topics", sb.getConfig("search.navigation", "").indexOf("topics",0) >= 0 ? 1 : 0);
 
diff --git a/htroot/yacy/search.java b/htroot/yacy/search.java
index 9078d26c5..0e3398476 100644
--- a/htroot/yacy/search.java
+++ b/htroot/yacy/search.java
@@ -121,6 +121,7 @@ public final class search {
         modifier.sitehost = post.get("sitehost", ""); if (modifier.sitehost.isEmpty()) modifier.sitehost = null;
         modifier.sitehash = post.get("sitehash", ""); if (modifier.sitehash.isEmpty()) modifier.sitehash = null;
         modifier.author = post.get("author", ""); if (modifier.author.isEmpty()) modifier.author = null;
+        modifier.collection = post.get("collection", ""); if (modifier.collection.isEmpty()) modifier.collection = null;
         modifier.filetype = post.get("filetype", ""); if (modifier.filetype.isEmpty()) modifier.filetype = null;
         modifier.protocol = post.get("protocol", ""); if (modifier.protocol.isEmpty()) modifier.protocol = null;
         modifier.parse(post.get("modifier", "").trim());
diff --git a/htroot/yacysearch.java b/htroot/yacysearch.java
index a8b3f7317..da8b295d3 100644
--- a/htroot/yacysearch.java
+++ b/htroot/yacysearch.java
@@ -364,7 +364,7 @@ public class yacysearch {
             querystring = modifier.parse(querystring);
 
             // read collection
-            modifier.collection = post.get("collection", "");
+            modifier.collection = post.get("collection", modifier.collection); // post arguments may overrule parsed collection values
             
             int stp = querystring.indexOf('*');
             if (stp >= 0) {
diff --git a/htroot/yacysearchtrailer.html b/htroot/yacysearchtrailer.html
index a88bd08a2..6fcbdc2f0 100644
--- a/htroot/yacysearchtrailer.html
+++ b/htroot/yacysearchtrailer.html
@@ -163,6 +163,21 @@ $(function() { $("#sidebarAuthors").accordion('activate', false); });
 ::#(/activate)#
 #(/nav-authors)#
 
+#(nav-collections)#::
+<ul class="nav nav-sidebar menugroup">
+<li><h3>Collection</h3></li>
+#{element}#
+<li><a href="#[url]#" class="MenuItemLink"><input type="checkbox" onchange="window.location.href='#[url]#'"#(on)# checked="checked"::#(/on)#/> #[name]# (#[count]#)</a></li>
+#{/element}#</ul>
+#(activate)#
+<script type="text/javascript">
+//<![CDATA[
+$(function() { $("#sidebarCollections").accordion('activate', false); });
+//]]>
+</script>
+::#(/activate)#
+#(/nav-collections)#
+
 #{nav-vocabulary}#
 <ul class="nav nav-sidebar menugroup">
 <li><h3>#[navname]#</h3></li>
diff --git a/htroot/yacysearchtrailer.java b/htroot/yacysearchtrailer.java
index dda4fd313..6dd8cabe6 100644
--- a/htroot/yacysearchtrailer.java
+++ b/htroot/yacysearchtrailer.java
@@ -265,6 +265,47 @@ public class yacysearchtrailer {
                 prop.put("nav-authors", 0); // this navigation is not useful
             }
         }
+        
+        // collection navigators
+        if (theSearch.collectionNavigator == null || theSearch.collectionNavigator.isEmpty()) {
+            prop.put("nav-collections", 0);
+        } else {
+            prop.put("nav-collections", 1);
+            navigatorIterator = theSearch.collectionNavigator.keys(false);
+            int i = 0, pos = 0, neg = 0;
+            String nav;
+            while (i < 10 && navigatorIterator.hasNext()) {
+                name = navigatorIterator.next().trim();
+                count = theSearch.collectionNavigator.get(name);
+                if (count == 0) {
+                    break;
+                }
+                nav = (name.indexOf(' ', 0) < 0) ? "collection%3A" + name : "collection%3A%28" + name.replace(" ", "+") + "%29";
+                if (theSearch.query.modifier.collection == null || !theSearch.query.modifier.collection.contains(name)) {
+                    pos++;
+                    prop.put("nav-collections_element_" + i + "_on", 1);
+                    prop.put(fileType, "nav-collections_element_" + i + "_modifier", nav);
+                } else {
+                    neg++;                    
+                    prop.put("nav-collections_element_" + i + "_on", 0);
+                    prop.put(fileType, "nav-collections_element_" + i + "_modifier", "-" + nav);
+                    nav="";
+                }
+                prop.put(fileType, "nav-collections_element_" + i + "_name", name);
+                prop.put(fileType, "nav-collections_element_" + i + "_url", QueryParams.navurl(fileType, 0, theSearch.query, nav, false).toString());
+                prop.put("nav-collections_element_" + i + "_count", count);
+                prop.put("nav-collections_element_" + i + "_nl", 1);
+                i++;
+            }
+            prop.put("nav-collections_element", i);
+            prop.put("nav-collections_activate", neg > 0 ? 1 : 0); // by default off
+            i--;
+            prop.put("nav-collections_element_" + i + "_nl", 0);
+            if (pos == 1 && neg == 0)
+             {
+                prop.put("nav-collections", 0); // this navigation is not useful
+            }
+        }
 
         // topics navigator
         final ScoreMap<String> topicNavigator = sb.index.connectedRWI() ? theSearch.getTopicNavigator(TOPWORDS_MAXCOUNT) : null;
diff --git a/htroot/yacysearchtrailer.json b/htroot/yacysearchtrailer.json
index 5009a28c4..4bc2abb30 100644
--- a/htroot/yacysearchtrailer.json
+++ b/htroot/yacysearchtrailer.json
@@ -63,7 +63,20 @@
         {"name": "#[name]#", "count": "#[count]#", "modifier": "#[modifier]#", "url": "#[url]#"}#(nl)#::,#(/nl)#
 #{/element}#
       ]
-    },#(/nav-authors)##{nav-vocabulary}#
+    },#(/nav-authors)##(nav-collections)#::
+    {
+      "facetname": "collections",
+      "displayname": "Collections",
+      "type": "String",
+      "min": "0",
+      "max": "0",
+      "mean": "0",
+      "elements": [
+#{element}#
+        {"name": "#[name]#", "count": "#[count]#", "modifier": "#[modifier]#", "url": "#[url]#"}#(nl)#::,#(/nl)#
+#{/element}#
+      ]
+    },#(/nav-collections)##{nav-vocabulary}#
     {
       "facetname": "#[navname]#",
       "displayname": "#[navname]#",
diff --git a/htroot/yacysearchtrailer.xml b/htroot/yacysearchtrailer.xml
index 489be7729..50fd565e9 100644
--- a/htroot/yacysearchtrailer.xml
+++ b/htroot/yacysearchtrailer.xml
@@ -20,6 +20,13 @@
 #{/element}#
 </yacy:facet>
 #(/nav-authors)#
+#(nav-collections)#::
+<yacy:facet name="collections" displayname="Collections" type="String" min="0" max="0" mean="0">
+#{element}#
+<yacy:element name="#[name]#" count="#[count]#" modifier="#[modifier]#" url="#[url]#"/>
+#{/element}#
+</yacy:facet>
+#(/nav-collections)#
 #(nav-filetypes)#::
 <yacy:facet name="filetypes" displayname="Filetypes" type="String" min="0" max="0" mean="0">
 #{element}#
diff --git a/source/net/yacy/cora/federate/solr/responsewriter/OpensearchResponseWriter.java b/source/net/yacy/cora/federate/solr/responsewriter/OpensearchResponseWriter.java
index e97d75c71..45b32d70f 100644
--- a/source/net/yacy/cora/federate/solr/responsewriter/OpensearchResponseWriter.java
+++ b/source/net/yacy/cora/federate/solr/responsewriter/OpensearchResponseWriter.java
@@ -267,6 +267,8 @@ public class OpensearchResponseWriter implements QueryResponseWriter {
         NamedList<Integer> protocols = facetFields == null ? null : (NamedList<Integer>) facetFields.get(CollectionSchema.url_protocol_s.getSolrFieldName());
         @SuppressWarnings("unchecked")
         NamedList<Integer> authors = facetFields == null ? null : (NamedList<Integer>) facetFields.get(CollectionSchema.author_sxt.getSolrFieldName());
+        @SuppressWarnings("unchecked")
+        NamedList<Integer> collections = facetFields == null ? null : (NamedList<Integer>) facetFields.get(CollectionSchema.collection_sxt.getSolrFieldName());
         
         if (domains != null) {
             openTag(writer, "yacy:facet name=\"domains\" displayname=\"Domains\" type=\"String\" min=\"0\" max=\"0\" mean=\"0\"");
@@ -288,6 +290,11 @@ public class OpensearchResponseWriter implements QueryResponseWriter {
             for (Map.Entry<String, Integer> entry: authors) facetEntry(writer, "author", entry.getKey(), Integer.toString(entry.getValue()));
             closeTag(writer, "yacy:facet");
         }
+        if (collections != null) {
+            openTag(writer, "yacy:facet name=\"collections\" displayname=\"Collections\" type=\"String\" min=\"0\" max=\"0\" mean=\"0\"");
+            for (Map.Entry<String, Integer> entry: collections) facetEntry(writer, "collection", entry.getKey(), Integer.toString(entry.getValue()));
+            closeTag(writer, "yacy:facet");
+        }
         closeTag(writer, "yacy:navigation");
         
         closeTag(writer, "channel");
diff --git a/source/net/yacy/cora/federate/solr/responsewriter/YJsonResponseWriter.java b/source/net/yacy/cora/federate/solr/responsewriter/YJsonResponseWriter.java
index 46c21c9e4..d95f3e21b 100644
--- a/source/net/yacy/cora/federate/solr/responsewriter/YJsonResponseWriter.java
+++ b/source/net/yacy/cora/federate/solr/responsewriter/YJsonResponseWriter.java
@@ -236,6 +236,8 @@ public class YJsonResponseWriter implements QueryResponseWriter {
         NamedList<Integer> protocols = facetFields == null ? null : (NamedList<Integer>) facetFields.get(CollectionSchema.url_protocol_s.getSolrFieldName());
         @SuppressWarnings("unchecked")
         NamedList<Integer> authors = facetFields == null ? null : (NamedList<Integer>) facetFields.get(CollectionSchema.author_sxt.getSolrFieldName());
+        @SuppressWarnings("unchecked")
+        NamedList<Integer> collections = facetFields == null ? null : (NamedList<Integer>) facetFields.get(CollectionSchema.collection_sxt.getSolrFieldName());
 
         if (domains != null) {
             writer.write("{\"facetname\":\"domains\",\"displayname\":\"Provider\",\"type\":\"String\",\"min\":\"0\",\"max\":\"0\",\"mean\":\"0\",\"elements\":[\n".toCharArray());
@@ -279,6 +281,15 @@ public class YJsonResponseWriter implements QueryResponseWriter {
             }
             writer.write("]},\n".toCharArray());
         }
+        if (collections != null) {
+            writer.write("{\"facetname\":\"collections\",\"displayname\":\"Collections\",\"type\":\"String\",\"min\":\"0\",\"max\":\"0\",\"mean\":\"0\",\"elements\":[\n".toCharArray());
+            for (int i = 0; i < collections.size(); i++) {
+                facetEntry(writer, "collection", collections.getName(i), Integer.toString(collections.getVal(i)));
+                if (i < collections.size() - 1) writer.write(',');
+                writer.write("\n");
+            }
+            writer.write("]},\n".toCharArray());
+        }
         writer.write("]}]}\n".toCharArray());
         
         if (jsonp != null) {
diff --git a/source/net/yacy/http/servlets/SolrSelectServlet.java b/source/net/yacy/http/servlets/SolrSelectServlet.java
index bdf5b72ce..7a6c06fce 100644
--- a/source/net/yacy/http/servlets/SolrSelectServlet.java
+++ b/source/net/yacy/http/servlets/SolrSelectServlet.java
@@ -78,7 +78,7 @@ import org.apache.solr.util.FastWriter;
 /*
  * taken from the Solr 3.6.0 code, which is now deprecated;
  * this is now done in Solr 4.x.x with org.apache.solr.servlet.SolrDispatchFilter
- * implemented as servlet (we don't use multicore)
+ * implemented as servlet
  */
 public class SolrSelectServlet extends HttpServlet {
     private static final long serialVersionUID = 1L;
diff --git a/source/net/yacy/search/query/QueryModifier.java b/source/net/yacy/search/query/QueryModifier.java
index 4f14161cd..1ec790732 100644
--- a/source/net/yacy/search/query/QueryModifier.java
+++ b/source/net/yacy/search/query/QueryModifier.java
@@ -55,26 +55,26 @@ public class QueryModifier {
         // parse protocol
         if ( querystring.indexOf("/https", 0) >= 0 ) {
             querystring = querystring.replace("/https", "");
-            protocol = "https";
+            this.protocol = "https";
             add("/https");
         } else if ( querystring.indexOf("/http", 0) >= 0 ) {
             querystring = querystring.replace("/http", "");
-            protocol = "http";
+            this.protocol = "http";
             add("/http");
         }
         if ( querystring.indexOf("/ftp", 0) >= 0 ) {
             querystring = querystring.replace("/ftp", "");
-            protocol = "ftp";
+            this.protocol = "ftp";
             add("/ftp");
         }
         if ( querystring.indexOf("/smb", 0) >= 0 ) {
             querystring = querystring.replace("/smb", "");
-            protocol = "smb";
+            this.protocol = "smb";
             add("/smb");
         }
         if ( querystring.indexOf("/file", 0) >= 0 ) {
             querystring = querystring.replace("/file", "");
-            protocol = "file";
+            this.protocol = "file";
             add("/file");
         }
         
@@ -91,21 +91,21 @@ public class QueryModifier {
             if ( ftb == -1 ) {
                 ftb = querystring.length();
             }
-            sitehost = querystring.substring(sp + 5, ftb);
-            querystring = querystring.replace("site:" + sitehost, "");
-            while ( sitehost.length() > 0 && sitehost.charAt(0) == '.' ) {
-                sitehost = sitehost.substring(1);
+            this.sitehost = querystring.substring(sp + 5, ftb);
+            querystring = querystring.replace("site:" + this.sitehost, "");
+            while ( this.sitehost.length() > 0 && this.sitehost.charAt(0) == '.' ) {
+                this.sitehost = this.sitehost.substring(1);
             }
             while ( sitehost.endsWith(".") ) {
-                sitehost = sitehost.substring(0, sitehost.length() - 1);
+                this.sitehost = this.sitehost.substring(0, this.sitehost.length() - 1);
             }
             try {
-                sitehash = DigestURL.hosthash(sitehost, sitehost.startsWith("ftp.") ? 21 : 80);
+                this.sitehash = DigestURL.hosthash(this.sitehost, this.sitehost.startsWith("ftp.") ? 21 : 80);
             } catch (MalformedURLException e) {
-                sitehash = "";
+                this.sitehash = "";
                 ConcurrentLog.logException(e);
             }
-            add("site:" + sitehost);
+            add("site:" + this.sitehost);
         }
         
         // parse author
@@ -116,31 +116,43 @@ public class QueryModifier {
             if ( quotes ) {
                 int ftb = querystring.indexOf(')', authori + 8);
                 if (ftb == -1) ftb = querystring.length() + 1;
-                author = querystring.substring(authori + 8, ftb);
-                querystring = querystring.replace("author:(" + author + ")", "");
+                this.author = querystring.substring(authori + 8, ftb);
+                querystring = querystring.replace("author:(" + this.author + ")", "");
                 add("author:(" + author + ")");
             } else {
                 int ftb = querystring.indexOf(' ', authori);
                 if ( ftb == -1 ) {
                     ftb = querystring.length();
                 }
-                author = querystring.substring(authori + 7, ftb);
-                querystring = querystring.replace("author:" + author, "");
+                this.author = querystring.substring(authori + 7, ftb);
+                querystring = querystring.replace("author:" + this.author, "");
                 add("author:" + author);
             }
         }
+        
+        // parse collection
+        final int collectioni = querystring.indexOf("collection:", 0);
+        if ( collectioni >= 0 ) {
+            int ftb = querystring.indexOf(' ', collectioni);
+            if ( ftb == -1 ) {
+                ftb = querystring.length();
+            }
+            this.collection = querystring.substring(collectioni + 11, ftb);
+            querystring = querystring.replace("collection:" + this.collection, "");
+            add("collection:" + this.collection);
+        }
 
         // parse language
         final int langi = querystring.indexOf("/language/");
         if (langi >= 0) {
             if (querystring.length() >= (langi + 12)) {
-                language = querystring.substring(langi + 10, langi + 12);
-                querystring = querystring.replace("/language/" + language, "");
-                if (language.length() == 2 && ISO639.exists(language)) { // only 2-digit codes valid
-                    language = language.toLowerCase();
-                    add("/language/" + language);
+                this.language = querystring.substring(langi + 10, langi + 12);
+                querystring = querystring.replace("/language/" + this.language, "");
+                if (this.language.length() == 2 && ISO639.exists(this.language)) { // only 2-digit codes valid
+                    this.language = this.language.toLowerCase();
+                    add("/language/" + this.language);
                 } else {
-                    language = null;
+                    this.language = null;
                 }
             }
         }
@@ -223,12 +235,17 @@ public class QueryModifier {
             fq.append(" AND ").append(CollectionSchema.author_sxt.getSolrFieldName()).append(":\"").append(this.author).append('\"');
         }
         
+        if (this.collection != null && this.collection.length() > 0 && fq.indexOf(CollectionSchema.collection_sxt.getSolrFieldName()) < 0) {
+            fq.append(" AND ").append(CollectionSchema.collection_sxt.getSolrFieldName()).append(":\"").append(this.collection).append('\"');
+        }
+        
         if (this.protocol != null && this.protocol.length() > 0 && fq.indexOf(CollectionSchema.url_protocol_s.getSolrFieldName()) < 0) {
             fq.append(" AND ").append(CollectionSchema.url_protocol_s.getSolrFieldName()).append(":\"").append(this.protocol).append('\"');
         }
 
         return fq;
     }
+    
     public void apply(serverObjects post) {
         
         final StringBuilder fq = apply(post.get(CommonParams.FQ,""));
diff --git a/source/net/yacy/search/query/QueryParams.java b/source/net/yacy/search/query/QueryParams.java
index af71cf6f6..17267b489 100644
--- a/source/net/yacy/search/query/QueryParams.java
+++ b/source/net/yacy/search/query/QueryParams.java
@@ -88,6 +88,7 @@ public final class QueryParams {
         defaultfacetfields.put("protocol", CollectionSchema.url_protocol_s);
         defaultfacetfields.put("filetype", CollectionSchema.url_file_ext_s);
         defaultfacetfields.put("authors", CollectionSchema.author_sxt);
+        defaultfacetfields.put("collections", CollectionSchema.collection_sxt);
         defaultfacetfields.put("language", CollectionSchema.language_s);
         //missing: namespace
     }
@@ -226,7 +227,7 @@ public final class QueryParams {
         this.solrSchema = indexSegment.fulltext().getDefaultConfiguration();
         for (String navkey: search_navigation) {
             CollectionSchema f = defaultfacetfields.get(navkey);
-            if (f != null && solrSchema.contains(f)) facetfields.add(f.getSolrFieldName());
+            if (f != null && solrSchema.contains(f)) this.facetfields.add(f.getSolrFieldName());
         }
         for (Tagging v: LibraryProvider.autotagging.getVocabularies()) this.facetfields.add(CollectionSchema.VOCABULARY_PREFIX + v.getName() + CollectionSchema.VOCABULARY_SUFFIX);
         this.maxfacets = defaultmaxfacets;
@@ -468,6 +469,11 @@ public final class QueryParams {
         if (this.modifier.author != null && this.modifier.author.length() > 0 && this.solrSchema.contains(CollectionSchema.author_sxt)) {
             fq.append(" AND ").append(CollectionSchema.author_sxt.getSolrFieldName()).append(":\"").append(this.modifier.author).append('\"');
         }
+
+        // add collection facets
+        if (this.modifier.collection != null && this.modifier.collection.length() > 0 && this.solrSchema.contains(CollectionSchema.collection_sxt)) {
+            fq.append(" AND ").append(QueryModifier.parseCollectionExpression(this.modifier.collection));
+        }
         
         if (this.modifier.protocol != null) {
             fq.append(" AND {!tag=").append(CollectionSchema.url_protocol_s.getSolrFieldName()).append("}").append(CollectionSchema.url_protocol_s.getSolrFieldName()).append(':').append(this.modifier.protocol);
@@ -509,10 +515,6 @@ public final class QueryParams {
             //params.setRows(Integer.MAX_VALUE);
         }
         
-        if (this.modifier.collection != null && this.modifier.collection.length() > 0) {
-            fq.append(" AND ").append(QueryModifier.parseCollectionExpression(this.modifier.collection));
-        }
-        
         return fq.length() > 0 ? fq.substring(5) : fq.toString();
     }
     
diff --git a/source/net/yacy/search/query/SearchEvent.java b/source/net/yacy/search/query/SearchEvent.java
index d851d3142..88c4fcb70 100644
--- a/source/net/yacy/search/query/SearchEvent.java
+++ b/source/net/yacy/search/query/SearchEvent.java
@@ -141,6 +141,7 @@ public final class SearchEvent {
     public final ScoreMap<String> locationNavigator; // a counter for the appearance of location coordinates
     public final ScoreMap<String> hostNavigator; // a counter for the appearance of host names
     public final ScoreMap<String> authorNavigator; // a counter for the appearances of authors
+    public final ScoreMap<String> collectionNavigator; // a counter for the appearances of collections
     public final ScoreMap<String> namespaceNavigator; // a counter for name spaces
     public final ScoreMap<String> protocolNavigator; // a counter for protocol types
     public final ScoreMap<String> filetypeNavigator; // a counter for file types
@@ -229,6 +230,7 @@ public final class SearchEvent {
         final String navcfg = Switchboard.getSwitchboard().getConfig("search.navigation", "")+",language";
         this.locationNavigator = navcfg.contains("location") ? new ConcurrentScoreMap<String>() : null;
         this.authorNavigator = navcfg.contains("authors") ? new ConcurrentScoreMap<String>() : null;
+        this.collectionNavigator = navcfg.contains("collections") ? new ConcurrentScoreMap<String>() : null;
         this.namespaceNavigator = navcfg.contains("namespace") ? new ConcurrentScoreMap<String>() : null;
         this.hostNavigator = navcfg.contains("hosts") ? new ConcurrentScoreMap<String>() : null;
         this.protocolNavigator = navcfg.contains("protocol") ? new ConcurrentScoreMap<String>() : null;
@@ -809,6 +811,11 @@ public final class SearchEvent {
             if (fcts != null) this.authorNavigator.inc(fcts);
         }
 
+        if (this.collectionNavigator != null) {
+            fcts = facets.get(CollectionSchema.collection_sxt.getSolrFieldName());
+            if (fcts != null) this.collectionNavigator.inc(fcts);
+        }
+
         if (this.protocolNavigator != null) {
             fcts = facets.get(CollectionSchema.url_protocol_s.getSolrFieldName());
             if (fcts != null) {