diff --git a/src/main/resources/com/atomgraph/linkeddatahub/ldh.ttl b/src/main/resources/com/atomgraph/linkeddatahub/ldh.ttl
index 9823751df..96aab82b1 100644
--- a/src/main/resources/com/atomgraph/linkeddatahub/ldh.ttl
+++ b/src/main/resources/com/atomgraph/linkeddatahub/ldh.ttl
@@ -576,14 +576,29 @@ dh:Item spin:constructor :TitleConstructor, :DescriptionConstructor, :PrimaryTop
         WHERE {}""" ;
     rdfs:isDefinedBy : .
 
+:ChildrenViewContructor a :Constructor ;
+    rdfs:label "Container content constructor" ;
+    sp:text """
+        PREFIX ldh:     <https://w3id.org/atomgraph/linkeddatahub#>
+        PREFIX rdf:   <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
+        PREFIX spin:    <http://spinrdf.org/spin#>
+
+        CONSTRUCT {
+            $this rdf:_1 [
+                a ldh:Object ;
+                rdf:value ldh:ChildrenView ;
+            ] .
+        }
+        WHERE {}""" ;
+    rdfs:isDefinedBy : .
+
 :MissingContainer a :MissingPropertyValue ;
     rdfs:label "Missing container" ;
     rdfs:comment "Requires items to have a parent container" ;
     sp:arg1 sioc:has_container ;
     rdfs:isDefinedBy : .
 
-dh:Container spin:constructor :TitleConstructor, :DescriptionConstructor, :PrimaryTopicConstructor ;
-    :template :ChildrenView .
+dh:Container spin:constructor :TitleConstructor, :DescriptionConstructor, :PrimaryTopicConstructor, :ChildrenViewContructor .
 
 :MissingParent a :MissingPropertyValue ;
     rdfs:label "Missing parent" ;
@@ -678,4 +693,4 @@ sd:Service spin:constructor :ServiceConstructor ;
       }
       WHERE {}""" ;
     rdfs:label "Service constructor" ;
-    rdfs:isDefinedBy : .
\ No newline at end of file
+    rdfs:isDefinedBy : .
diff --git a/src/main/webapp/static/com/atomgraph/linkeddatahub/xsl/bootstrap/2.3.2/client/block.xsl b/src/main/webapp/static/com/atomgraph/linkeddatahub/xsl/bootstrap/2.3.2/client/block.xsl
index a673a28dd..8653920b0 100644
--- a/src/main/webapp/static/com/atomgraph/linkeddatahub/xsl/bootstrap/2.3.2/client/block.xsl
+++ b/src/main/webapp/static/com/atomgraph/linkeddatahub/xsl/bootstrap/2.3.2/client/block.xsl
@@ -115,6 +115,14 @@ exclude-result-prefixes="#all"
 
     <!-- TEMPLATES -->
 
+    <!-- identity transform -->
+   
+    <xsl:template match="@* | node()" mode="ldh:Identity">
+        <xsl:copy>
+            <xsl:apply-templates select="@* | node()" mode="#current"/>
+        </xsl:copy>
+    </xsl:template>
+    
     <!-- render row -->
     
     <xsl:template match="*" mode="ldh:RenderRow" as="(function(item()?) as map(*))?">
diff --git a/src/main/webapp/static/com/atomgraph/linkeddatahub/xsl/bootstrap/2.3.2/client/block/chart.xsl b/src/main/webapp/static/com/atomgraph/linkeddatahub/xsl/bootstrap/2.3.2/client/block/chart.xsl
index 228f60fcc..920567d98 100644
--- a/src/main/webapp/static/com/atomgraph/linkeddatahub/xsl/bootstrap/2.3.2/client/block/chart.xsl
+++ b/src/main/webapp/static/com/atomgraph/linkeddatahub/xsl/bootstrap/2.3.2/client/block/chart.xsl
@@ -39,6 +39,54 @@ exclude-result-prefixes="#all"
 
     <!-- TEMPLATES -->
     
+    <!-- set chart properties -->
+
+    <xsl:template match="ldh:chartType | ldh:categoryVarName | ldh:categoryProperty | ldh:seriesVarName | ldh:seriesProperty" mode="ldh:Identity" priority="1"/>
+
+    <xsl:template match="*[rdf:type/@rdf:resource = '&ldh;ResultSetChart']" mode="ldh:Identity" priority="1">
+        <xsl:param name="chart-type" as="xs:anyURI" tunnel="yes"/>
+        <xsl:param name="category" as="xs:string?" tunnel="yes"/>
+        <xsl:param name="series" as="xs:string*" tunnel="yes"/>
+
+        <xsl:copy>
+            <xsl:apply-templates select="@* | node()" mode="#current"/>
+            
+            <xsl:for-each select="$chart-type">
+                <ldh:chartType rdf:resource="{.}"/>
+            </xsl:for-each>
+            <xsl:for-each select="$category">
+                <ldh:categoryVarName>
+                    <xsl:value-of select="."/>
+                </ldh:categoryVarName>
+            </xsl:for-each>
+            <xsl:for-each select="$series">
+                <ldh:seriesVarName>
+                    <xsl:value-of select="."/>
+                </ldh:seriesVarName>
+            </xsl:for-each>
+        </xsl:copy>
+    </xsl:template>
+    
+    <xsl:template match="*[rdf:type/@rdf:resource = '&ldh;GraphChart']" mode="ldh:Identity" priority="1">
+        <xsl:param name="chart-type" as="xs:anyURI" tunnel="yes"/>
+        <xsl:param name="category" as="xs:string?" tunnel="yes"/>
+        <xsl:param name="series" as="xs:string*" tunnel="yes"/>
+
+        <xsl:copy>
+            <xsl:apply-templates select="@* | node()" mode="#current"/>
+
+            <xsl:for-each select="$chart-type">
+                <ldh:chartType rdf:resource="{.}"/>
+            </xsl:for-each>
+            <xsl:for-each select="$category">
+                <ldh:categoryProperty rdf:resource="{.}"/>
+            </xsl:for-each>
+            <xsl:for-each select="$series">
+                <ldh:seriesProperty rdf:resource="{.}"/>
+            </xsl:for-each>
+        </xsl:copy>
+    </xsl:template>
+    
     <!-- TO-DO: make 'data-table' configurable -->
     <xsl:template name="ac:draw-chart">
         <xsl:param name="data-table"/>
@@ -216,9 +264,9 @@ exclude-result-prefixes="#all"
         <xsl:param name="button-class" select="'btn'" as="xs:string?"/>
         <xsl:param name="accept-charset" select="'UTF-8'" as="xs:string?"/>
         <xsl:param name="enctype" as="xs:string?"/>
-        <xsl:param name="chart-type-id" select="'chart-type'" as="xs:string"/>
-        <xsl:param name="category-id" select="'category'" as="xs:string"/>
-        <xsl:param name="series-id" select="'series'" as="xs:string"/>
+        <xsl:param name="chart-type-id" select="'chart-type-' || generate-id()" as="xs:string"/>
+        <xsl:param name="category-id" select="'category-' || generate-id()" as="xs:string"/>
+        <xsl:param name="series-id" select="'series-' || generate-id()" as="xs:string"/>
         <xsl:param name="form-actions" as="element()?">
             <div class="form-actions">
                 <button class="btn btn-primary btn-save-chart" type="button">
@@ -627,6 +675,67 @@ exclude-result-prefixes="#all"
         <ixsl:set-style name="cursor" select="'default'" object="ixsl:page()//body"/>
     </xsl:template>
     
+    <!-- save chart onclick -->
+    <!-- TO-DO: use @typeof in match so that we don't need a custom button.btn-save-chart class -->
+    
+    <xsl:template match="div[@typeof]//button[contains-token(@class, 'btn-save-chart')]" mode="ixsl:onclick">
+        <ixsl:set-style name="cursor" select="'progress'" object="ixsl:page()//body"/>
+        <xsl:variable name="block" select="ancestor::div[contains-token(@class, 'block')][1]" as="element()"/>
+        <xsl:variable name="container" select="ancestor::div[@typeof][1]" as="element()"/>
+        <xsl:variable name="about" select="$block/@about" as="xs:anyURI"/>
+        <xsl:variable name="query-uri" select="$container//descendant::*[@property = '&spin;query']/@resource" as="xs:anyURI"/>
+        <xsl:variable name="chart-type" select="$container//form//select[contains-token(@class, 'chart-type')]/ixsl:get(., 'value')" as="xs:anyURI?"/>
+        <xsl:variable name="category" select="$container//form//select[contains-token(@class, 'chart-category')]/ixsl:get(., 'value')" as="xs:string?"/>
+        <xsl:variable name="series" as="xs:string*">
+            <xsl:for-each select="$container//form//select[contains-token(@class, 'chart-series')]">
+                <xsl:variable name="select" select="." as="element()"/>
+                <xsl:for-each select="0 to xs:integer(ixsl:get(., 'selectedOptions.length')) - 1">
+                    <xsl:sequence select="ixsl:get(ixsl:call(ixsl:get($select, 'selectedOptions'), 'item', [ . ]), 'value')"/>
+                </xsl:for-each>
+            </xsl:for-each>
+        </xsl:variable>
+        <xsl:variable name="method" select="'PATCH'" as="xs:string"/>
+        <xsl:variable name="action" select="ac:absolute-path(ldh:base-uri(.))" as="xs:anyURI"/>
+        <xsl:variable name="accept" select="'application/rdf+xml'" as="xs:string"/>
+        <xsl:variable name="etag" select="ixsl:get(ixsl:get(ixsl:get(ixsl:window(), 'LinkedDataHub.contents'), '`' || ac:absolute-path(ldh:base-uri(.)) || '`'), 'etag')" as="xs:string"/>
+        <!-- not using ldh:base-uri(.) because it goes stale when DOM is replaced -->
+        <xsl:variable name="doc" select="ixsl:get(ixsl:get(ixsl:get(ixsl:window(), 'LinkedDataHub.contents'), '`' || ac:absolute-path(xs:anyURI(ixsl:location())) || '`'), 'results')" as="document-node()"/>
+        <xsl:variable name="chart" select="key('resources', $about, $doc)" as="element()"/>
+        <!-- update the properties on the chart resource -->
+        <xsl:variable name="chart" as="element()">
+            <xsl:apply-templates select="$chart" mode="ldh:Identity">
+                <xsl:with-param name="chart-type" select="$chart-type" tunnel="yes"/>
+                <xsl:with-param name="series" select="$series" tunnel="yes"/>
+                <xsl:with-param name="category" select="$category" tunnel="yes"/>
+            </xsl:apply-templates>
+        </xsl:variable>
+        <xsl:variable name="triples" select="ldh:descriptions-to-triples($chart)" as="element()*"/>
+        <xsl:variable name="update-string" select="ldh:insertdelete-update(ldh:triples-to-bgp(ldh:uri-po-pattern($about)), ldh:triples-to-bgp($triples), ldh:triples-to-bgp(ldh:uri-po-pattern($about)))" as="xs:string"/>
+        <xsl:variable name="resources" as="document-node()">
+            <xsl:document>
+                <rdf:RDF>
+                    <xsl:sequence select="ldh:triples-to-descriptions($triples)"/>
+                </rdf:RDF>
+            </xsl:document>
+        </xsl:variable>
+        <xsl:variable name="request-uri" select="ldh:href($ldt:base, ac:absolute-path($ldh:requestUri), map{}, $action)" as="xs:anyURI"/>
+        <!-- If-Match header checks preconditions, i.e. that the graph has not been modified in the meanwhile -->
+        <xsl:variable name="request" select="map{ 'method': $method, 'href': $request-uri, 'media-type': 'application/sparql-update', 'body': $update-string, 'headers': map{ 'If-Match': $etag, 'Accept': 'application/rdf+xml', 'Cache-Control': 'no-cache' } }" as="map(*)"/>
+        <xsl:variable name="context" as="map(*)" select="
+          map{
+            'request': $request,
+            'doc-uri': ac:absolute-path(ldh:base-uri(.)),
+            'block': $block,
+            'resources': $resources
+          }"/>
+        <ixsl:promise select="
+          ixsl:http-request($context('request'))                          (: Step 1: send initial request :)
+            => ixsl:then(ldh:rethread-response($context, ?))              (: Step 2: attach response to context :)
+            => ixsl:then(ldh:handle-response#1)                           (: Step 3: handle 429s, etc. :)
+            => ixsl:then(ldh:row-form-response#1)
+        "/>
+    </xsl:template>
+    
     <!-- CALLBACKS -->
 
     <!-- chart query response -->
diff --git a/src/main/webapp/static/com/atomgraph/linkeddatahub/xsl/bootstrap/2.3.2/client/block/query.xsl b/src/main/webapp/static/com/atomgraph/linkeddatahub/xsl/bootstrap/2.3.2/client/block/query.xsl
index e9585b9ee..932338fb4 100644
--- a/src/main/webapp/static/com/atomgraph/linkeddatahub/xsl/bootstrap/2.3.2/client/block/query.xsl
+++ b/src/main/webapp/static/com/atomgraph/linkeddatahub/xsl/bootstrap/2.3.2/client/block/query.xsl
@@ -43,17 +43,9 @@ exclude-result-prefixes="#all"
         <xsl:attribute name="class" select="concat($class, ' ', 'btn-run-query')"/>
     </xsl:template>
     
-   <!-- identity transform -->
-   
-    <xsl:template match="@* | node()" mode="ldh:SetQueryString">
-        <xsl:copy>
-            <xsl:apply-templates select="@* | node()" mode="#current"/>
-        </xsl:copy>
-    </xsl:template>
-    
     <!-- set query string -->
 
-    <xsl:template match="sp:text/text()" mode="ldh:SetQueryString" priority="1">
+    <xsl:template match="sp:text/text()" mode="ldh:Identity" priority="1">
         <xsl:param name="query-string" as="xs:string" tunnel="yes"/>
 
         <xsl:sequence select="$query-string"/>
@@ -467,7 +459,7 @@ exclude-result-prefixes="#all"
 
         <!-- replace the query string (sp:text value) on the query resource -->
         <xsl:variable name="query" as="element()">
-            <xsl:apply-templates select="$query" mode="ldh:SetQueryString">
+            <xsl:apply-templates select="$query" mode="ldh:Identity">
                 <xsl:with-param name="query-string" select="$query-string" tunnel="yes"/>
             </xsl:apply-templates>
         </xsl:variable>
diff --git a/src/main/webapp/static/com/atomgraph/linkeddatahub/xsl/bootstrap/2.3.2/client/form.xsl b/src/main/webapp/static/com/atomgraph/linkeddatahub/xsl/bootstrap/2.3.2/client/form.xsl
index 54850fd87..dedf0fd58 100644
--- a/src/main/webapp/static/com/atomgraph/linkeddatahub/xsl/bootstrap/2.3.2/client/form.xsl
+++ b/src/main/webapp/static/com/atomgraph/linkeddatahub/xsl/bootstrap/2.3.2/client/form.xsl
@@ -107,7 +107,7 @@ WHERE
     <xsl:template match="*[rdf:type/@rdf:resource = ('&spin;ConstraintViolation', '&sh;ValidationResult', '&sh;ValidationReport', '&http;Response')]" mode="bs2:Form" priority="3"/>
 
     <!-- suppress the system properties of document resources (they are set automatically by LinkedDataHub) -->
-    <xsl:template match="*[rdf:type/@rdf:resource = ('&def;Root', '&dh;Container', '&dh;Item')]/dct:created | *[rdf:type/@rdf:resource = ('&def;Root', '&dh;Container', '&dh;Item')]/dct:modified | *[rdf:type/@rdf:resource = ('&def;Root', '&dh;Container', '&dh;Item')]/sioc:has_container | *[rdf:type/@rdf:resource = ('&def;Root', '&dh;Container', '&dh;Item')]/sioc:has_parent | *[rdf:type/@rdf:resource = ('&def;Root', '&dh;Container', '&dh;Item')]/dct:creator | *[rdf:type/@rdf:resource = ('&def;Root', '&dh;Container', '&dh;Item')]/acl:owner | *[rdf:type/@rdf:resource = ('&def;Root', '&dh;Container', '&dh;Item')]/*[namespace-uri() = '&rdf;'][starts-with(local-name(), '_')]" mode="bs2:FormControl" priority="1"/>
+    <xsl:template match="*[rdf:type/@rdf:resource = ('&def;Root', '&dh;Container', '&dh;Item')]/dct:created | *[rdf:type/@rdf:resource = ('&def;Root', '&dh;Container', '&dh;Item')]/dct:modified | *[rdf:type/@rdf:resource = ('&def;Root', '&dh;Container', '&dh;Item')]/sioc:has_container | *[rdf:type/@rdf:resource = ('&def;Root', '&dh;Container', '&dh;Item')]/sioc:has_parent | *[rdf:type/@rdf:resource = ('&def;Root', '&dh;Container', '&dh;Item')]/dct:creator | *[rdf:type/@rdf:resource = ('&def;Root', '&dh;Container', '&dh;Item')]/acl:owner | *[rdf:type/@rdf:resource = ('&def;Root', '&dh;Container')]/*[namespace-uri() = '&rdf;'][starts-with(local-name(), '_')][@rdf:resource] | *[rdf:type/@rdf:resource = '&dh;Item']/*[namespace-uri() = '&rdf;'][starts-with(local-name(), '_')]" mode="bs2:FormControl" priority="1"/>
     
     <!-- canonicalize XML in rdf:XMLLiterals -->
     <xsl:template match="json:string[@key = 'object'][ends-with(., '^^&rdf;XMLLiteral')]" mode="ldh:CanonicalizeXML" priority="1">
diff --git a/src/main/webapp/static/com/atomgraph/linkeddatahub/xsl/bootstrap/2.3.2/layout.xsl b/src/main/webapp/static/com/atomgraph/linkeddatahub/xsl/bootstrap/2.3.2/layout.xsl
index 940b29e8d..4238e0e9d 100644
--- a/src/main/webapp/static/com/atomgraph/linkeddatahub/xsl/bootstrap/2.3.2/layout.xsl
+++ b/src/main/webapp/static/com/atomgraph/linkeddatahub/xsl/bootstrap/2.3.2/layout.xsl
@@ -805,8 +805,10 @@ LIMIT   100
         <xsl:param name="typeof" select="key('resources', ac:absolute-path(ldh:base-uri(.)))/rdf:type/@rdf:resource/xs:anyURI(.)" as="xs:anyURI*"/>
         <xsl:param name="doc-types" select="key('resources', ac:absolute-path(ldh:base-uri(.)))/rdf:type/@rdf:resource[ . = ('&def;Root', '&dh;Container', '&dh;Item')]" as="xs:anyURI*"/>
         <!-- take care not to load unnecessary documents over HTTP when $doc-types is empty -->
-        <xsl:param name="block-values" select="if (exists($doc-types)) then (if (doc-available(resolve-uri('ns?query=ASK%20%7B%7D', $ldt:base))) then (ldh:query-result(map{}, resolve-uri('ns', $ldt:base), $template-query || ' VALUES $Type { ' || string-join(for $type in $doc-types return '&lt;' || $type || '&gt;', ' ') || ' }')//srx:binding[@name = 'block']/srx:uri/xs:anyURI(.)) else ()) else ()" as="xs:anyURI*"/>
-        <xsl:param name="has-content" select="key('resources', key('resources', ac:absolute-path(ldh:base-uri(.)))/rdf:*[starts-with(local-name(), '_')]/@rdf:resource) or exists($block-values)" as="xs:boolean"/>
+        <xsl:param name="template-block-uris" select="if (exists($doc-types)) then (if (doc-available(resolve-uri('ns?query=ASK%20%7B%7D', $ldt:base))) then (ldh:query-result(map{}, resolve-uri('ns', $ldt:base), $template-query || ' VALUES $Type { ' || string-join(for $type in $doc-types return '&lt;' || $type || '&gt;', ' ') || ' }')//srx:binding[@name = 'block']/srx:uri/xs:anyURI(.)) else ()) else ()" as="xs:anyURI*"/>
+        <xsl:param name="block-uris" select="key('resources', ac:absolute-path(ldh:base-uri(.)))/rdf:*[starts-with(local-name(), '_')]/@rdf:resource" as="xs:anyURI*"/>
+        <!-- document has content when either explicitly declared document-level blocks exist or template-declared class-level blocks exist -->
+        <xsl:param name="has-content" select="exists(for $block-uri in $block-uris return (if (doc-available(ac:document-uri($block-uri))) then key('resources', $block-uri, document(ac:document-uri($block-uri))) else ())) or exists($template-block-uris)" as="xs:boolean"/>
 
         <div>
             <xsl:if test="$id">
@@ -838,7 +840,7 @@ LIMIT   100
                 </xsl:when>
                 <!-- check if the current document has content or its class has content -->
                 <xsl:when test="(empty($ac:mode) and $has-content) or $ac:mode = '&ldh;ContentMode'">
-                    <xsl:for-each select="$block-values">
+                    <xsl:for-each select="$template-block-uris">
                         <xsl:if test="doc-available(ac:document-uri(.))">
                             <xsl:apply-templates select="key('resources', ., document(ac:document-uri(.)))" mode="bs2:Row"/>
                         </xsl:if>