diff --git a/src/_locales/en/messages.json b/src/_locales/en/messages.json
index e03bb85..a79b536 100644
--- a/src/_locales/en/messages.json
+++ b/src/_locales/en/messages.json
@@ -342,6 +342,10 @@
         "message": "Collapse placeholder of blocked elements",
         "description": "English: Collapse placeholder of blocked elements"
     },
+    "settingsCollapseBlacklisted" : {
+        "message": "Collapse placeholder of blacklisted elements",
+        "description": "A setting in the dashboard's Settings pane: 'blacklisted' means 'for which there is a specific block rule', 'specific' means 'a rule for which the destination hostname is not `*`'"
+    },
     "settingsNoscriptTagsSpoofed" : {
         "message": "Spoof <code><noscript></code> tags when 1st-party scripts are blocked",
         "description": "This appears in the Settings pane in the dashboard"
diff --git a/src/css/dashboard-common.css b/src/css/dashboard-common.css
index d78e52e..9d465ff 100644
--- a/src/css/dashboard-common.css
+++ b/src/css/dashboard-common.css
@@ -36,7 +36,9 @@ a {
 button {
     padding: 0.3em 0.5em;
     }
-
+input[disabled] + label {
+    color: gray;
+    }
 .para {
     width: 40em;
     }
diff --git a/src/js/background.js b/src/js/background.js
index e178ce7..7d3b4ec 100644
--- a/src/js/background.js
+++ b/src/js/background.js
@@ -91,6 +91,7 @@ return {
         clearBrowserCache: true,
         clearBrowserCacheAfter: 60,
         cloudStorageEnabled: false,
+        collapseBlacklisted: true,
         collapseBlocked: false,
         colorBlindFriendly: false,
         deleteCookies: false,
diff --git a/src/js/contentscript.js b/src/js/contentscript.js
index b15957e..4717065 100644
--- a/src/js/contentscript.js
+++ b/src/js/contentscript.js
@@ -109,71 +109,86 @@ vAPI.contentscriptEndInjected = true;
 // https://github.com/gorhill/uMatrix/issues/45
 
 var collapser = (function() {
-    var timer = null;
-    var requestId = 1;
-    var newRequests = [];
-    var pendingRequests = {};
-    var pendingRequestCount = 0;
-    var srcProps = {
-        'img': 'src'
+    var resquestIdGenerator = 1,
+        processTimer,
+        toProcess = [],
+        toFilter = [],
+        toCollapse = new Map(),
+        cachedBlockedMap,
+        cachedBlockedMapHash,
+        cachedBlockedMapTimer,
+        reURLPlaceholder = /\{\{url\}\}/g;
+    var src1stProps = {
+        'embed': 'src',
+        'iframe': 'src',
+        'img': 'src',
+        'object': 'data'
     };
-    var reURLplaceholder = /\{\{url\}\}/g;
-
-    var PendingRequest = function(target) {
-        this.id = requestId++;
-        this.target = target;
-        pendingRequests[this.id] = this;
-        pendingRequestCount += 1;
+    var src2ndProps = {
+        'img': 'srcset'
     };
-
-    // Because a while ago I have observed constructors are faster than
-    // literal object instanciations.
-    var BouncingRequest = function(id, tagName, url) {
-        this.id = id;
-        this.tagName = tagName;
-        this.url = url;
-        this.blocked = false;
+    var tagToTypeMap = {
+        embed: 'media',
+        iframe: 'frame',
+        img: 'image',
+        object: 'media'
+    };
+    var cachedBlockedSetClear = function() {
+        cachedBlockedMap =
+        cachedBlockedMapHash =
+        cachedBlockedMapTimer = undefined;
     };
 
+    // https://github.com/chrisaljoudi/uBlock/issues/174
+    //   Do not remove fragment from src URL
     var onProcessed = function(response) {
-        if ( !response ) {
+        if ( !response ) { // This happens if uBO is disabled or restarted.
+            toCollapse.clear();
             return;
         }
-        var requests = response.requests;
-        if ( requests === null || Array.isArray(requests) === false ) {
+
+        var targets = toCollapse.get(response.id);
+        if ( targets === undefined ) { return; }
+        toCollapse.delete(response.id);
+        if ( cachedBlockedMapHash !== response.hash ) {
+            cachedBlockedMap = new Map(response.blockedResources);
+            cachedBlockedMapHash = response.hash;
+            if ( cachedBlockedMapTimer !== undefined ) {
+                clearTimeout(cachedBlockedMapTimer);
+            }
+            cachedBlockedMapTimer = vAPI.setTimeout(cachedBlockedSetClear, 30000);
+        }
+        if ( cachedBlockedMap === undefined || cachedBlockedMap.size === 0 ) {
             return;
         }
-        var collapse = response.collapse;
-        var placeholders = response.placeholders;
-        var i = requests.length;
-        var request, entry, target, tagName, docurl, replaced;
-        while ( i-- ) {
-            request = requests[i];
-            if ( pendingRequests.hasOwnProperty(request.id) === false ) {
-                continue;
-            }
-            entry = pendingRequests[request.id];
-            delete pendingRequests[request.id];
-            pendingRequestCount -= 1;
 
-            // Not blocked
-            if ( !request.blocked ) {
-                continue;
+        var placeholders = response.placeholders,
+            tag, prop, src, collapsed, docurl, replaced;
+
+        for ( var target of targets ) {
+            tag = target.localName;
+            prop = src1stProps[tag];
+            if ( prop === undefined ) { continue; }
+            src = target[prop];
+            if ( typeof src !== 'string' || src.length === 0 ) {
+                prop = src2ndProps[tag];
+                if ( prop === undefined ) { continue; }
+                src = target[prop];
+                if ( typeof src !== 'string' || src.length === 0 ) { continue; }
             }
-
-            target = entry.target;
-
-            // No placeholders
-            if ( collapse ) {
+            collapsed = cachedBlockedMap.get(tagToTypeMap[tag] + ' ' + src);
+            if ( collapsed === undefined ) { continue; }
+            if ( collapsed ) {
                 target.style.setProperty('display', 'none', 'important');
+                target.hidden = true;
                 continue;
             }
-
-            tagName = target.localName;
-
-            // Special case: iframe
-            if ( tagName === 'iframe' ) {
-                docurl = 'data:text/html,' + encodeURIComponent(placeholders.iframe.replace(reURLplaceholder, request.url));
+            if ( tag === 'iframe' ) {
+                docurl =
+                    'data:text/html,' +
+                    encodeURIComponent(
+                        placeholders.iframe.replace(reURLPlaceholder, src)
+                    );
                 replaced = false;
                 // Using contentWindow.location prevent tainting browser
                 // history -- i.e. breaking back button (seen on Chromium).
@@ -189,148 +204,125 @@ var collapser = (function() {
                 }
                 continue;
             }
-
-            // Everything else
-            target.setAttribute(srcProps[tagName], placeholders[tagName]);
+            target.setAttribute(src1stProps[tag], placeholders[tag]);
             target.style.setProperty('border', placeholders.border, 'important');
             target.style.setProperty('background', placeholders.background, 'important');
         }
-
-        // Renew map: I believe that even if all properties are deleted, an
-        // object will still use more memory than a brand new one.
-        if ( pendingRequestCount === 0 ) {
-            pendingRequests = {};
-        }
     };
 
     var send = function() {
-        timer = null;
-        vAPI.messaging.send('contentscript.js', {
-            what: 'evaluateURLs',
-            requests: newRequests
-        }, onProcessed);
-        newRequests = [];
+        processTimer = undefined;
+        toCollapse.set(resquestIdGenerator, toProcess);
+        var msg = {
+            what: 'lookupBlockedCollapsibles',
+            id: resquestIdGenerator,
+            toFilter: toFilter,
+            hash: cachedBlockedMapHash
+        };
+        vAPI.messaging.send('contentscript.js', msg, onProcessed);
+        toProcess = [];
+        toFilter = [];
+        resquestIdGenerator += 1;
     };
 
     var process = function(delay) {
-        if ( newRequests.length === 0 ) {
-            return;
-        }
+        if ( toProcess.length === 0 ) { return; }
         if ( delay === 0 ) {
-            clearTimeout(timer);
+            if ( processTimer !== undefined ) {
+                clearTimeout(processTimer);
+            }
             send();
-        } else if ( timer === null ) {
-            timer = vAPI.setTimeout(send, delay || 50);
+        } else if ( processTimer === undefined ) {
+            processTimer = vAPI.setTimeout(send, delay || 47);
+        }
+    };
+
+    var add = function(target) {
+        toProcess.push(target);
+    };
+
+    var addMany = function(targets) {
+        var i = targets.length;
+        while ( i-- ) {
+            toProcess.push(targets[i]);
         }
     };
 
     var iframeSourceModified = function(mutations) {
         var i = mutations.length;
         while ( i-- ) {
-            addFrameNode(mutations[i].target, true);
+            addIFrame(mutations[i].target, true);
         }
         process();
     };
-    var iframeSourceObserver = null;
+    var iframeSourceObserver;
     var iframeSourceObserverOptions = {
         attributes: true,
         attributeFilter: [ 'src' ]
     };
 
-    var addFrameNode = function(iframe, dontObserve) {
+    var addIFrame = function(iframe, dontObserve) {
         // https://github.com/gorhill/uBlock/issues/162
         // Be prepared to deal with possible change of src attribute.
         if ( dontObserve !== true ) {
-            if ( iframeSourceObserver === null ) {
+            if ( iframeSourceObserver === undefined ) {
                 iframeSourceObserver = new MutationObserver(iframeSourceModified);
             }
             iframeSourceObserver.observe(iframe, iframeSourceObserverOptions);
         }
-        // https://github.com/chrisaljoudi/uBlock/issues/174
-        // Do not remove fragment from src URL
         var src = iframe.src;
-        if ( src.lastIndexOf('http', 0) !== 0 ) {
-            return;
-        }
-        var req = new PendingRequest(iframe);
-        newRequests.push(new BouncingRequest(req.id, 'iframe', src));
-    };
-
-    var addNode = function(target) {
-        var tagName = target.localName;
-        if ( tagName === 'iframe' ) {
-            addFrameNode(target);
-            return;
-        }
-        var prop = srcProps[tagName];
-        if ( prop === undefined ) {
-            return;
-        }
-        // https://github.com/chrisaljoudi/uBlock/issues/174
-        // Do not remove fragment from src URL
-        var src = target[prop];
-        if ( typeof src !== 'string' || src === '' ) {
-            return;
-        }
-        if ( src.lastIndexOf('http', 0) !== 0 ) {
-            return;
-        }
-        var req = new PendingRequest(target);
-        newRequests.push(new BouncingRequest(req.id, tagName, src));
+        if ( src === '' || typeof src !== 'string' ) { return; }
+        if ( src.startsWith('http') === false ) { return; }
+        toFilter.push({ type: 'frame', url: iframe.src });
+        add(iframe);
     };
 
-    var addNodes = function(nodes) {
-        var node;
-        var i = nodes.length;
+    var addIFrames = function(iframes) {
+        var i = iframes.length;
         while ( i-- ) {
-            node = nodes[i];
-            if ( node.nodeType === 1 ) {
-                addNode(node);
-            }
+            addIFrame(iframes[i]);
         }
     };
 
-    var addBranches = function(branches) {
-        var root;
-        var i = branches.length;
+    var addNodeList = function(nodeList) {
+        var node,
+            i = nodeList.length;
         while ( i-- ) {
-            root = branches[i];
-            if ( root.nodeType === 1 ) {
-                addNode(root);
-                // blocked images will be reported by onResourceFailed
-                addNodes(root.querySelectorAll('iframe'));
+            node = nodeList[i];
+            if ( node.nodeType !== 1 ) { continue; }
+            if ( node.localName === 'iframe' ) {
+                addIFrame(node);
+            }
+            if ( node.childElementCount !== 0 ) {
+                addIFrames(node.querySelectorAll('iframe'));
             }
         }
     };
 
-    // Listener to collapse blocked resources.
-    // - Future requests not blocked yet
-    // - Elements dynamically added to the page
-    // - Elements which resource URL changes
     var onResourceFailed = function(ev) {
-        addNode(ev.target);
-        process();
+        if ( tagToTypeMap[ev.target.localName] !== undefined ) {
+            add(ev.target);
+            process();
+        }
     };
     document.addEventListener('error', onResourceFailed, true);
 
     vAPI.shutdown.add(function() {
-        if ( timer !== null ) {
-            clearTimeout(timer);
-            timer = null;
-        }
-        if ( iframeSourceObserver !== null ) {
+        document.removeEventListener('error', onResourceFailed, true);
+        if ( iframeSourceObserver !== undefined ) {
             iframeSourceObserver.disconnect();
-            iframeSourceObserver = null;
+            iframeSourceObserver = undefined;
+        }
+        if ( processTimer !== undefined ) {
+            clearTimeout(processTimer);
+            processTimer = undefined;
         }
-        document.removeEventListener('error', onResourceFailed, true);
-        newRequests = [];
-        pendingRequests = {};
-        pendingRequestCount = 0;
     });
 
     return {
-        addNodes: addNodes,
-        addBranches: addBranches,
+        addMany: addMany,
+        addIFrames: addIFrames,
+        addNodeList: addNodeList,
         process: process
     };
 })();
@@ -345,10 +337,6 @@ var hasInlineScript = function(nodeList, summary) {
         if ( node.nodeType !== 1 ) {
             continue;
         }
-        if ( typeof node.localName !== 'string' ) {
-            continue;
-        }
-
         if ( node.localName === 'script' ) {
             text = node.textContent.trim();
             if ( text === '' ) {
@@ -357,7 +345,6 @@ var hasInlineScript = function(nodeList, summary) {
             summary.inlineScript = true;
             break;
         }
-
         if ( node.localName === 'a' && node.href.lastIndexOf('javascript', 0) === 0 ) {
             summary.inlineScript = true;
             break;
@@ -368,8 +355,6 @@ var hasInlineScript = function(nodeList, summary) {
     }
 };
 
-/******************************************************************************/
-
 var nodeListsAddedHandler = function(nodeLists) {
     var i = nodeLists.length;
     if ( i === 0 ) {
@@ -385,7 +370,7 @@ var nodeListsAddedHandler = function(nodeLists) {
         if ( summary.inlineScript === false ) {
             hasInlineScript(nodeLists[i], summary);
         }
-        collapser.addBranches(nodeLists[i]);
+        collapser.addNodeList(nodeLists[i]);
     }
     if ( summary.mustReport ) {
         vAPI.messaging.send('contentscript.js', summary);
@@ -415,7 +400,8 @@ var nodeListsAddedHandler = function(nodeLists) {
 
     vAPI.messaging.send('contentscript.js', summary);
 
-    collapser.addNodes(document.querySelectorAll('iframe,img'));
+    collapser.addMany(document.querySelectorAll('img'));
+    collapser.addIFrames(document.querySelectorAll('iframe'));
     collapser.process();
 })();
 
@@ -427,6 +413,9 @@ var nodeListsAddedHandler = function(nodeLists) {
 // Added node lists will be cumulated here before being processed
 
 (function() {
+    // This fixes http://acid3.acidtests.org/
+    if ( !document.body ) { return; }
+
     var addedNodeLists = [];
     var addedNodeListsTimer = null;
 
@@ -439,28 +428,19 @@ var nodeListsAddedHandler = function(nodeLists) {
     // https://github.com/gorhill/uBlock/issues/205
     // Do not handle added node directly from within mutation observer.
     var treeMutationObservedHandlerAsync = function(mutations) {
-        var iMutation = mutations.length;
-        var nodeList;
+        var iMutation = mutations.length,
+            nodeList;
         while ( iMutation-- ) {
             nodeList = mutations[iMutation].addedNodes;
             if ( nodeList.length !== 0 ) {
                 addedNodeLists.push(nodeList);
             }
         }
-        // I arbitrarily chose 250 ms for now:
-        // I have to compromise between the overhead of processing too few 
-        // nodes too often and the delay of many nodes less often. There is nothing
-        // time critical here.
         if ( addedNodeListsTimer === null ) {
-            addedNodeListsTimer = vAPI.setTimeout(treeMutationObservedHandler, 250);
+            addedNodeListsTimer = vAPI.setTimeout(treeMutationObservedHandler, 47);
         }
     };
 
-    // This fixes http://acid3.acidtests.org/
-    if ( !document.body ) {
-        return;
-    }
-
     // https://github.com/gorhill/httpswitchboard/issues/176
     var treeObserver = new MutationObserver(treeMutationObservedHandlerAsync);
     treeObserver.observe(document.body, {
diff --git a/src/js/matrix.js b/src/js/matrix.js
index bcfad2e..24650ff 100644
--- a/src/js/matrix.js
+++ b/src/js/matrix.js
@@ -39,6 +39,9 @@ var uniqueIdGenerator = 1;
 var Matrix = function() {
     this.id = uniqueIdGenerator++;
     this.reset();
+    this.sourceRegister = '';
+    this.decomposedSourceRegister = [''];
+    this.specificityRegister = 0;
 };
 
 /******************************************************************************/
@@ -141,9 +144,7 @@ var isIPAddress = function(hostname) {
 /******************************************************************************/
 
 var toBroaderHostname = function(hostname) {
-    if ( hostname === '*' ) {
-        return '';
-    }
+    if ( hostname === '*' ) { return ''; }
     if ( isIPAddress(hostname) ) {
         return toBroaderIPAddress(hostname);
     }
@@ -192,6 +193,20 @@ Matrix.prototype.reset = function() {
 
 /******************************************************************************/
 
+Matrix.prototype.decomposeSource = function(srcHostname) {
+    if ( srcHostname === this.sourceRegister ) { return; }
+    var hn = srcHostname;
+    this.decomposedSourceRegister[0] = this.sourceRegister = hn;
+    var i = 1;
+    for (;;) {
+        hn = toBroaderHostname(hn);
+        this.decomposedSourceRegister[i++] = hn;
+        if ( hn === '' ) { break; }
+    }
+};
+
+/******************************************************************************/
+
 // Copy another matrix to self. Do this incrementally to minimize impact on
 // a live matrix.
 
@@ -331,10 +346,13 @@ Matrix.prototype.evaluateCell = function(srcHostname, desHostname, type) {
 /******************************************************************************/
 
 Matrix.prototype.evaluateCellZ = function(srcHostname, desHostname, type) {
-    var bitOffset = typeBitOffsets.get(type);
-    var s = srcHostname;
-    var v;
+    this.decomposeSource(srcHostname);
+
+    var bitOffset = typeBitOffsets.get(type),
+        s, v, i = 0;
     for (;;) {
+        s = this.decomposedSourceRegister[i++];
+        if ( s === '' ) { break; }
         v = this.rules.get(s + ' ' + desHostname);
         if ( v !== undefined ) {
             v = v >> bitOffset & 3;
@@ -342,9 +360,6 @@ Matrix.prototype.evaluateCellZ = function(srcHostname, desHostname, type) {
                 return v;
             }
         }
-        // TODO: external rules? (for presets)
-        s = toBroaderHostname(s);
-        if ( s === '' ) { break; }
     }
     // srcHostname is '*' at this point
 
@@ -366,6 +381,7 @@ Matrix.prototype.evaluateCellZ = function(srcHostname, desHostname, type) {
 
 Matrix.prototype.evaluateCellZXY = function(srcHostname, desHostname, type) {
     // Matrix filtering switch
+    this.specificityRegister = 0;
     if ( this.evaluateSwitchZ('matrix-off', srcHostname) ) {
         return Matrix.GreenIndirect;
     }
@@ -377,11 +393,13 @@ Matrix.prototype.evaluateCellZXY = function(srcHostname, desHostname, type) {
     // evaluating net requests.
 
     // Specific-hostname specific-type cell
+    this.specificityRegister = 1;
     var r = this.evaluateCellZ(srcHostname, desHostname, type);
     if ( r === 1 ) { return Matrix.RedDirect; }
     if ( r === 2 ) { return Matrix.GreenDirect; }
 
     // Specific-hostname any-type cell
+    this.specificityRegister = 2;
     var rl = this.evaluateCellZ(srcHostname, desHostname, '*');
     if ( rl === 1 ) { return Matrix.RedIndirect; }
 
@@ -390,10 +408,9 @@ Matrix.prototype.evaluateCellZXY = function(srcHostname, desHostname, type) {
 
     // Ancestor cells, up to 1st-party destination domain
     if ( firstPartyDesDomain !== '' ) {
+        this.specificityRegister = 3;
         for (;;) {
-            if ( d === firstPartyDesDomain ) {
-                break;
-            }
+            if ( d === firstPartyDesDomain ) { break; }
             d = d.slice(d.indexOf('.') + 1);
 
             // specific-hostname specific-type cell
@@ -420,11 +437,10 @@ Matrix.prototype.evaluateCellZXY = function(srcHostname, desHostname, type) {
     }
 
     // Keep going, up to root
+    this.specificityRegister = 4;
     for (;;) {
         d = toBroaderHostname(d);
-        if ( d === '*' ) {
-            break;
-        }
+        if ( d === '*' ) { break; }
 
         // specific-hostname specific-type cell
         r = this.evaluateCellZ(srcHostname, d, type);
@@ -438,6 +454,7 @@ Matrix.prototype.evaluateCellZXY = function(srcHostname, desHostname, type) {
     }
 
     // Any-hostname specific-type cells
+    this.specificityRegister = 5;
     r = this.evaluateCellZ(srcHostname, '*', type);
     // Line below is strict-blocking
     if ( r === 1 ) { return Matrix.RedIndirect; }
@@ -446,6 +463,7 @@ Matrix.prototype.evaluateCellZXY = function(srcHostname, desHostname, type) {
     if ( r === 2 ) { return Matrix.GreenIndirect; }
 
     // Any-hostname any-type cell
+    this.specificityRegister = 6;
     r = this.evaluateCellZ(srcHostname, '*', '*');
     if ( r === 1 ) { return Matrix.RedIndirect; }
     if ( r === 2 ) { return Matrix.GreenIndirect; }
@@ -534,12 +552,14 @@ Matrix.prototype.evaluateSwitch = function(switchName, srcHostname) {
 
 Matrix.prototype.evaluateSwitchZ = function(switchName, srcHostname) {
     var bitOffset = switchBitOffsets.get(switchName);
-    if ( bitOffset === undefined ) {
-        return false;
-    }
-    var bits;
-    var s = srcHostname;
+    if ( bitOffset === undefined ) { return false; }
+
+    this.decomposeSource(srcHostname);
+
+    var s, bits, i = 0;
     for (;;) {
+        s = this.decomposedSourceRegister[i++];
+        if ( s === '' ) { break; }
         bits = this.switches.get(s) || 0;
         if ( bits !== 0 ) {
             bits = bits >> bitOffset & 3;
@@ -547,10 +567,6 @@ Matrix.prototype.evaluateSwitchZ = function(switchName, srcHostname) {
                 return bits === 1;
             }
         }
-        s = toBroaderHostname(s);
-        if ( s === '' ) {
-            break;
-        }
     }
     return false;
 };
diff --git a/src/js/messaging.js b/src/js/messaging.js
index 797abd0..6fa1360 100644
--- a/src/js/messaging.js
+++ b/src/js/messaging.js
@@ -427,68 +427,58 @@ var contentScriptSummaryHandler = function(tabId, details) {
 /******************************************************************************/
 
 var contentScriptLocalStorageHandler = function(tabId, pageURL) {
-    var µmuri = µm.URI.set(pageURL);
-    var response = µm.mustBlock(µm.scopeFromURL(pageURL), µmuri.hostname, 'cookie');
-    µm.recordFromTabId(
-        tabId,
-        'cookie',
-        µmuri.rootURL() + '/{localStorage}',
-        response
+    var tabContext = µm.tabContextManager.lookup(tabId);
+    if ( tabContext === null ) { return; }
+
+    var blocked = µm.mustBlock(
+        tabContext.rootHostname,
+        µm.URI.hostnameFromURI(pageURL),
+        'cookie'
     );
-    response = response && µm.userSettings.deleteLocalStorage;
-    if ( response ) {
+
+    var pageStore = µm.pageStoreFromTabId(tabId);
+    if ( pageStore !== null ) {
+        var requestURL = µm.URI.originFromURI(pageURL) + '/{localStorage}';
+        pageStore.recordRequest('cookie', requestURL, blocked);
+        µm.logger.writeOne(tabId, 'net', tabContext.rootHostname, requestURL, 'cookie', blocked);
+    }
+
+    var removeStorage = blocked && µm.userSettings.deleteLocalStorage;
+    if ( removeStorage ) {
         µm.localStorageRemovedCounter++;
     }
-    return response;
+
+    return removeStorage;
 };
 
 /******************************************************************************/
 
 // Evaluate many URLs against the matrix.
 
-var evaluateURLs = function(tabId, requests) {
-    var collapse = µm.userSettings.collapseBlocked;
+var lookupBlockedCollapsibles = function(tabId, requests) {
     var response = {
-        collapse: collapse,
-        requests: requests
+        blockedResources: [],
+        hash: requests.hash,
+        id: requests.id,
+        placeholders: placeholders
     };
 
-    // Create evaluation context
     var tabContext = µm.tabContextManager.lookup(tabId);
     if ( tabContext === null ) {
         return response;
     }
-    var rootHostname = tabContext.rootHostname;
-
-    //console.debug('messaging.js/contentscript.js: processing %d requests', requests.length);
 
     var pageStore = µm.pageStoreFromTabId(tabId);
-    var µmuri = µm.URI;
-    var typeMap = tagNameToRequestTypeMap;
-    var request, type;
-    var i = requests.length;
-    while ( i-- ) {
-        request = requests[i];
-        type = typeMap[request.tagName];
-        request.blocked = µm.mustBlock(
-            rootHostname,
-            µmuri.hostnameFromURI(request.url),
-            type
-        );
-        // https://github.com/gorhill/uMatrix/issues/205
-        // If blocked, the URL must be recorded by the page store, so as to ensure
-        // they are properly reflected in the matrix.
-        if ( request.blocked && pageStore ) {
-            pageStore.recordRequest(type, request.url, true);
-        }
+    if ( pageStore !== null ) {
+        pageStore.lookupBlockedCollapsibles(requests, response);
     }
 
-    if ( collapse ) {
-        placeholders = null;
-        return response;
-    }
+    // TODO: evaluate whether the issue reported below still exists.
+    //   https://github.com/gorhill/uMatrix/issues/205
+    //   If blocked, the URL must be recorded by the page store, so as to
+    //   ensure they are properly reflected in the matrix.
 
-    if ( placeholders === null ) {
+    if ( response.placeholders === null ) {
         placeholders = {
             background:
                 vAPI.localStorage.getItem('placeholderBackground') ||
@@ -505,19 +495,12 @@ var evaluateURLs = function(tabId, requests) {
         };
         placeholders.iframe =
             placeholders.iframe.replace('{{bg}}', placeholders.background);
+        response.placeholders = placeholders;
     }
-    response.placeholders = placeholders;
 
     return response;
 };
 
-/******************************************************************************/
-
-var tagNameToRequestTypeMap = {
-    'iframe': 'frame',
-       'img': 'image'
-};
-
 var placeholders = null;
 
 /******************************************************************************/
@@ -544,8 +527,8 @@ var onMessage = function(request, sender, callback) {
         contentScriptSummaryHandler(tabId, request);
         break;
 
-    case 'evaluateURLs':
-        response = evaluateURLs(tabId, request.requests);
+    case 'lookupBlockedCollapsibles':
+        response = lookupBlockedCollapsibles(tabId, request);
         break;
 
     case 'mustRenderNoscriptTags?':
diff --git a/src/js/pagestats.js b/src/js/pagestats.js
index f180449..af01c64 100644
--- a/src/js/pagestats.js
+++ b/src/js/pagestats.js
@@ -25,117 +25,245 @@
 
 µMatrix.pageStoreFactory = (function() {
 
-    var µm = µMatrix;
-    var pageStoreJunkyard = [];
-
-    // Ref: Given a URL, returns a (somewhat) unique 32-bit value
-    // Based on: FNV32a
-    // http://www.isthe.com/chongo/tech/comp/fnv/index.html#FNV-reference-source
-    // The rest is custom, suited for µMatrix.
-    var uidFromURL = function(uri) {
-        var hint = 0x811c9dc5;
-        var i = uri.length;
-        while ( i-- ) {
-            hint ^= uri.charCodeAt(i) | 0;
-            hint += (hint<<1) + (hint<<4) + (hint<<7) + (hint<<8) + (hint<<24) | 0;
-            hint >>>= 0;
+/******************************************************************************/
+
+var µm = µMatrix;
+
+/******************************************************************************/
+
+var BlockedCollapsibles = function() {
+    this.boundPruneAsyncCallback = this.pruneAsyncCallback.bind(this);
+    this.blocked = new Map();
+    this.hash = 0;
+    this.timer = null;
+};
+
+BlockedCollapsibles.prototype = {
+
+    shelfLife: 10 * 1000,
+
+    add: function(type, url, isSpecific) {
+        if ( this.blocked.size === 0 ) { this.pruneAsync(); }
+        var now = Date.now() / 1000 | 0;
+        // The following "trick" is to encode the specifity into the lsb of the
+        // time stamp so as to avoid to have to allocate a memory structure to
+        // store both time stamp and specificity.
+        if ( isSpecific ) {
+            now |= 0x00000001;
+        } else {
+            now &= 0xFFFFFFFE;
         }
-        return hint;
-    };
+        this.blocked.set(type + ' ' + url, now);
+        this.hash = now;
+    },
+
+    reset: function() {
+        this.blocked.clear();
+        this.hash = 0;
+        if ( this.timer !== null ) {
+            clearTimeout(this.timer);
+            this.timer = null;
+        }
+    },
 
-    function PageStore(tabContext) {
-        this.requestStats = µm.requestStatsFactory();
-        this.off = false;
-        this.init(tabContext);
+    pruneAsync: function() {
+        if ( this.timer === null ) {
+            this.timer = vAPI.setTimeout(
+                this.boundPruneAsyncCallback,
+                this.shelfLife * 2
+            );
+        }
+    },
+
+    pruneAsyncCallback: function() {
+        this.timer = null;
+        var obsolete = Date.now() - this.shelfLife;
+        for ( var entry of this.blocked ) {
+            if ( entry[1] <= obsolete ) {
+                this.blocked.delete(entry[0]);
+            }
+        }
+        if ( this.blocked.size !== 0 ) { this.pruneAsync(); }
     }
+};
+
+/******************************************************************************/
+
+// Ref: Given a URL, returns a (somewhat) unique 32-bit value
+// Based on: FNV32a
+// http://www.isthe.com/chongo/tech/comp/fnv/index.html#FNV-reference-source
+// The rest is custom, suited for uMatrix.
+
+var PageStore = function(tabContext) {
+    this.hostnameTypeCells = new Map();
+    this.domains = new Set();
+    this.blockedCollapsibles = new BlockedCollapsibles();
+    this.requestStats = µm.requestStatsFactory();
+    this.off = false;
+    this.init(tabContext);
+};
+
+PageStore.prototype = {
 
-    PageStore.prototype = {
-        init: function(tabContext) {
-            this.tabId = tabContext.tabId;
-            this.rawUrl = tabContext.rawURL;
-            this.pageUrl = tabContext.normalURL;
-            this.pageHostname = tabContext.rootHostname;
-            this.pageDomain =  tabContext.rootDomain;
-            this.title = '';
-            this.hostnameTypeCells = new Map();
-            this.domains = new Set();
-            this.allHostnamesString = ' ';
-            this.requestStats.reset();
-            this.distinctRequestCount = 0;
-            this.perLoadAllowedRequestCount = 0;
-            this.perLoadBlockedRequestCount = 0;
+    collapsibleTypes: new Set([ 'image' ]),
+    pageStoreJunkyard: [],
+
+    init: function(tabContext) {
+        this.tabId = tabContext.tabId;
+        this.rawUrl = tabContext.rawURL;
+        this.pageUrl = tabContext.normalURL;
+        this.pageHostname = tabContext.rootHostname;
+        this.pageDomain =  tabContext.rootDomain;
+        this.title = '';
+        this.hostnameTypeCells.clear();
+        this.domains.clear();
+        this.allHostnamesString = ' ';
+        this.blockedCollapsibles.reset();
+        this.requestStats.reset();
+        this.distinctRequestCount = 0;
+        this.perLoadAllowedRequestCount = 0;
+        this.perLoadBlockedRequestCount = 0;
+        this.incinerationTimer = null;
+        this.mtxContentModifiedTime = 0;
+        this.mtxCountModifiedTime = 0;
+        return this;
+    },
+
+    dispose: function() {
+        this.rawUrl = '';
+        this.pageUrl = '';
+        this.pageHostname = '';
+        this.pageDomain = '';
+        this.title = '';
+        this.hostnameTypeCells.clear();
+        this.domains.clear();
+        this.allHostnamesString = ' ';
+        this.blockedCollapsibles.reset();
+        if ( this.incinerationTimer !== null ) {
+            clearTimeout(this.incinerationTimer);
             this.incinerationTimer = null;
-            this.mtxContentModifiedTime = 0;
-            this.mtxCountModifiedTime = 0;
-            return this;
-        },
-        dispose: function() {
-            this.hostnameTypeCells.clear();
-            this.rawUrl = '';
-            this.pageUrl = '';
-            this.pageHostname = '';
-            this.pageDomain = '';
-            this.title = '';
-            this.domains.clear();
-            this.allHostnamesString = ' ';
-            if ( this.incinerationTimer !== null ) {
-                clearTimeout(this.incinerationTimer);
-                this.incinerationTimer = null;
-            }
-            if ( pageStoreJunkyard.length < 8 ) {
-                pageStoreJunkyard.push(this);
-            }
-        },
-        recordRequest: function(type, url, block) {
-            var hostname = µm.URI.hostnameFromURI(url);
-
-            // Store distinct network requests. This is used to:
-            // - remember which hostname/type were seen
-            // - count the number of distinct URLs for any given
-            //   hostname-type pair
-            var key = hostname + ' ' + type,
-                uids = this.hostnameTypeCells.get(key);
-            if ( uids === undefined ) {
-                this.hostnameTypeCells.set(key, (uids = new Set()));
-            } else if ( uids.size > 99 ) {
-                return;
-            }
-            var uid = uidFromURL(url);
-            if ( uids.has(uid) ) { return; }
-            uids.add(uid);
-
-            // Count blocked/allowed requests
-            this.requestStats.record(type, block);
-
-            // https://github.com/gorhill/httpswitchboard/issues/306
-            // If it is recorded locally, record globally
-            µm.requestStats.record(type, block);
-            µm.updateBadgeAsync(this.tabId);
-
-            if ( block !== false ) {
-                this.perLoadBlockedRequestCount++;
-            } else {
-                this.perLoadAllowedRequestCount++;
-            }
+        }
+        if ( this.pageStoreJunkyard.length < 8 ) {
+            this.pageStoreJunkyard.push(this);
+        }
+    },
+
+    cacheBlockedCollapsible: function(type, url, specificity) {
+        if ( this.collapsibleTypes.has(type) ) {
+            this.blockedCollapsibles.add(
+                type,
+                url,
+                specificity !== 0 && specificity < 5
+            );
+        }
+    },
+
+    lookupBlockedCollapsibles: function(request, response) {
+        var tabContext = µm.tabContextManager.lookup(this.tabId);
+        if ( tabContext === null ) { return; }
 
-            this.distinctRequestCount++;
-            this.mtxCountModifiedTime = Date.now();
+        var collapseBlacklisted = µm.userSettings.collapseBlacklisted,
+            collapseBlocked = µm.userSettings.collapseBlocked,
+            entry;
 
-            if ( this.domains.has(hostname) === false ) {
-                this.domains.add(hostname);
-                this.allHostnamesString += hostname + ' ';
-                this.mtxContentModifiedTime = Date.now();
+        var blockedResources = response.blockedResources;
+
+        if (
+            Array.isArray(request.toFilter) &&
+            request.toFilter.length !== 0
+        ) {
+            var roothn = tabContext.rootHostname,
+                hnFromURI = µm.URI.hostnameFromURI,
+                tMatrix = µm.tMatrix;
+            for ( entry of request.toFilter ) {
+                if ( tMatrix.mustBlock(roothn, hnFromURI(entry.url), entry.type) === false ) {
+                    continue;
+                }
+                blockedResources.push([
+                    entry.type + ' ' + entry.url,
+                    collapseBlocked ||
+                    collapseBlacklisted && tMatrix.specificityRegister !== 0 &&
+                    tMatrix.specificityRegister < 5
+                ]);
             }
         }
-    };
 
-    return function pageStoreFactory(tabContext) {
-        var entry = pageStoreJunkyard.pop();
-        if ( entry ) {
-            return entry.init(tabContext);
+        if ( this.blockedCollapsibles.hash === response.hash ) { return; }
+        response.hash = this.blockedCollapsibles.hash;
+
+        for ( entry of this.blockedCollapsibles.blocked ) {
+            blockedResources.push([
+                entry[0],
+                collapseBlocked || collapseBlacklisted && (entry[1] & 1) !== 0
+            ]);
+        }
+    },
+
+    recordRequest: function(type, url, block) {
+        // Store distinct network requests. This is used to:
+        // - remember which hostname/type were seen
+        // - count the number of distinct URLs for any given
+        //   hostname-type pair
+        var hostname = µm.URI.hostnameFromURI(url),
+            key = hostname + ' ' + type,
+            uids = this.hostnameTypeCells.get(key);
+        if ( uids === undefined ) {
+            this.hostnameTypeCells.set(key, (uids = new Set()));
+        } else if ( uids.size > 99 ) {
+            return;
+        }
+        var uid = this.uidFromURL(url);
+        if ( uids.has(uid) ) { return; }
+        uids.add(uid);
+
+        // Count blocked/allowed requests
+        this.requestStats.record(type, block);
+
+        // https://github.com/gorhill/httpswitchboard/issues/306
+        // If it is recorded locally, record globally
+        µm.requestStats.record(type, block);
+        µm.updateBadgeAsync(this.tabId);
+
+        if ( block !== false ) {
+            this.perLoadBlockedRequestCount++;
+        } else {
+            this.perLoadAllowedRequestCount++;
+        }
+
+        this.distinctRequestCount++;
+        this.mtxCountModifiedTime = Date.now();
+
+        if ( this.domains.has(hostname) === false ) {
+            this.domains.add(hostname);
+            this.allHostnamesString += hostname + ' ';
+            this.mtxContentModifiedTime = Date.now();
+        }
+    },
+
+    uidFromURL: function(uri) {
+        var hint = 0x811c9dc5,
+            i = uri.length;
+        while ( i-- ) {
+            hint ^= uri.charCodeAt(i) | 0;
+            hint += (hint<<1) + (hint<<4) + (hint<<7) + (hint<<8) + (hint<<24) | 0;
+            hint >>>= 0;
         }
-        return new PageStore(tabContext);
-    };
+        return hint;
+    }
+};
+
+/******************************************************************************/
+
+return function pageStoreFactory(tabContext) {
+    var entry = PageStore.prototype.pageStoreJunkyard.pop();
+    if ( entry ) {
+        return entry.init(tabContext);
+    }
+    return new PageStore(tabContext);
+};
+
+/******************************************************************************/
+
 })();
 
 /******************************************************************************/
diff --git a/src/js/settings.js b/src/js/settings.js
index 9717fe3..1bf0a15 100644
--- a/src/js/settings.js
+++ b/src/js/settings.js
@@ -53,16 +53,16 @@ function changeMatrixSwitch(name, state) {
 
 /******************************************************************************/
 
-function onChangeValueHandler(uelem, setting, min, max) {
+function onChangeValueHandler(elem, setting, min, max) {
     var oldVal = cachedSettings.userSettings[setting];
-    var newVal = Math.round(parseFloat(uelem.val()));
+    var newVal = Math.round(parseFloat(elem.value));
     if ( typeof newVal !== 'number' ) {
         newVal = oldVal;
     } else {
         newVal = Math.max(newVal, min);
         newVal = Math.min(newVal, max);
     }
-    uelem.val(newVal);
+    elem.value = newVal;
     if ( newVal !== oldVal ) {
         changeUserSettings(setting, newVal);
     }
@@ -71,50 +71,89 @@ function onChangeValueHandler(uelem, setting, min, max) {
 /******************************************************************************/
 
 function prepareToDie() {
-    onChangeValueHandler(uDom('#delete-unused-session-cookies-after'), 'deleteUnusedSessionCookiesAfter', 15, 1440);
-    onChangeValueHandler(uDom('#clear-browser-cache-after'), 'clearBrowserCacheAfter', 15, 1440);
+    onChangeValueHandler(
+        uDom.nodeFromId('deleteUnusedSessionCookiesAfter'),
+        'deleteUnusedSessionCookiesAfter',
+        15, 1440
+    );
+    onChangeValueHandler(
+        uDom.nodeFromId('clearBrowserCacheAfter'),
+        'clearBrowserCacheAfter',
+        15, 1440
+    );
 }
 
 /******************************************************************************/
 
-var installEventHandlers = function() {
-    uDom('input[name="displayTextSize"]').on('change', function(){
-        changeUserSettings('displayTextSize', this.value);
-    });
-
-    uDom('#popupScopeLevel').on('change', function(){
-        changeUserSettings('popupScopeLevel', this.value);
-    });
+function onInputChanged(ev) {
+    var target = ev.target;
+
+    switch ( target.id ) {
+    case 'displayTextSizeNormal':
+    case 'displayTextSizeLarge':
+        changeUserSettings('displayTextSize', target.value);
+        break;
+    case 'clearBrowserCache':
+    case 'cloudStorageEnabled':
+    case 'collapseBlacklisted':
+    case 'collapseBlocked':
+    case 'colorBlindFriendly':
+    case 'deleteCookies':
+    case 'deleteLocalStorage':
+    case 'deleteUnusedSessionCookies':
+    case 'iconBadgeEnabled':
+    case 'processHyperlinkAuditing':
+        changeUserSettings(target.id, target.checked);
+        break;
+    case 'noMixedContent':
+    case 'processReferer':
+        changeMatrixSwitch(
+            target.getAttribute('data-matrix-switch'),
+            target.checked
+        );
+        break;
+    case 'deleteUnusedSessionCookiesAfter':
+        onChangeValueHandler(target, 'deleteUnusedSessionCookiesAfter', 15, 1440);
+        break;
+    case 'clearBrowserCacheAfter':
+        onChangeValueHandler(target, 'clearBrowserCacheAfter', 15, 1440);
+        break;
+    case 'popupScopeLevel':
+        changeUserSettings('popupScopeLevel', target.value);
+        break;
+    default:
+        break;
+    }
 
-    uDom('[data-setting-bool]').on('change', function(){
-        var settingName = this.getAttribute('data-setting-bool');
-        if ( typeof settingName === 'string' && settingName !== '' ) {
-            changeUserSettings(settingName, this.checked);
-        }
-    });
+    switch ( target.id ) {
+    case 'collapseBlocked':
+        synchronizeWidgets();
+        break;
+    default:
+        break;
+    }
+}
 
-    uDom('[data-matrix-switch]').on('change', function(){
-        var switchName = this.getAttribute('data-matrix-switch');
-        if ( typeof switchName === 'string' && switchName !== '' ) {
-            changeMatrixSwitch(switchName, this.checked);
-        }
-    });
+/******************************************************************************/
 
-    uDom('#delete-unused-session-cookies-after').on('change', function(){
-        onChangeValueHandler(uDom(this), 'deleteUnusedSessionCookiesAfter', 15, 1440);
-    });
-    uDom('#clear-browser-cache-after').on('change', function(){
-        onChangeValueHandler(uDom(this), 'clearBrowserCacheAfter', 15, 1440);
-    });
+function synchronizeWidgets() {
+    var e1, e2;
 
-    // https://github.com/gorhill/httpswitchboard/issues/197
-    uDom(window).on('beforeunload', prepareToDie);
-};
+    e1 = uDom.nodeFromId('collapseBlocked');
+    e2 = uDom.nodeFromId('collapseBlacklisted');
+    if ( e1.checked ) {
+        e2.setAttribute('disabled', '');
+    } else {
+        e2.removeAttribute('disabled');
+    }
+}
 
 /******************************************************************************/
 
-uDom.onLoad(function() {
-    var onSettingsReceived = function(settings) {
+vAPI.messaging.send(
+    'settings.js',
+    { what: 'getUserSettings' },
+    function onSettingsReceived(settings) {
         // Cache copy
         cachedSettings = settings;
 
@@ -122,10 +161,7 @@ uDom.onLoad(function() {
         var matrixSwitches = settings.matrixSwitches;
 
         uDom('[data-setting-bool]').forEach(function(elem){
-            var settingName = elem.attr('data-setting-bool');
-            if ( typeof settingName === 'string' && settingName !== '' ) {
-                elem.prop('checked', userSettings[settingName] === true);
-            }
+            elem.prop('checked', userSettings[elem.prop('id')] === true);
         });
 
         uDom('[data-matrix-switch]').forEach(function(elem){
@@ -140,18 +176,19 @@ uDom.onLoad(function() {
         });
 
         uDom.nodeFromId('popupScopeLevel').value = userSettings.popupScopeLevel;
+        uDom.nodeFromId('deleteUnusedSessionCookiesAfter').value =
+            userSettings.deleteUnusedSessionCookiesAfter;
+        uDom.nodeFromId('clearBrowserCacheAfter').value =
+            userSettings.clearBrowserCacheAfter;
 
-        uDom('#delete-unused-session-cookies-after').val(userSettings.deleteUnusedSessionCookiesAfter);
-        uDom('#clear-browser-cache-after').val(userSettings.clearBrowserCacheAfter);
+        synchronizeWidgets();
 
-        installEventHandlers();
-    };
-    vAPI.messaging.send(
-        'settings.js',
-        { what: 'getUserSettings' },
-        onSettingsReceived
-    );
-});
+        document.addEventListener('change', onInputChanged);
+
+        // https://github.com/gorhill/httpswitchboard/issues/197
+        uDom(window).on('beforeunload', prepareToDie);
+    }
+);
 
 /******************************************************************************/
 
diff --git a/src/js/tab.js b/src/js/tab.js
index 7eca608..ed96b1f 100644
--- a/src/js/tab.js
+++ b/src/js/tab.js
@@ -552,19 +552,6 @@ vAPI.tabs.registerListeners();
 
 /******************************************************************************/
 
-// Log a request
-
-µm.recordFromTabId = function(tabId, type, url, blocked) {
-    var pageStore = this.pageStoreFromTabId(tabId);
-    if ( pageStore === null ) {
-        return;
-    }
-    pageStore.recordRequest(type, url, blocked);
-    this.logger.writeOne(tabId, 'net', pageStore.pageHostname, url, type, blocked);
-};
-
-/******************************************************************************/
-
 µm.forceReload = function(tabId, bypassCache) {
     vAPI.tabs.reload(tabId, bypassCache);
 };
diff --git a/src/js/traffic.js b/src/js/traffic.js
index 2a52c97..c25b4c1 100644
--- a/src/js/traffic.js
+++ b/src/js/traffic.js
@@ -75,26 +75,19 @@ var onBeforeRootFrameRequestHandler = function(details) {
 // Intercept and filter web requests according to white and black lists.
 
 var onBeforeRequestHandler = function(details) {
-    var µm = µMatrix,
-        µmuri = µm.URI;
-
-    // rhill 2014-02-17: Ignore 'filesystem:': this can happen when listening
-    // to 'chrome-extension://'.
-    var requestScheme = µmuri.schemeFromURI(details.url);
-    if ( requestScheme === 'filesystem' ) {
-        return;
-    }
-
     var requestType = requestTypeNormalizer[details.type] || 'other';
 
     // https://github.com/gorhill/httpswitchboard/issues/303
     // Wherever the main doc comes from, create a receiver page URL: synthetize
     // one if needed.
-    if ( requestType === 'doc' && details.parentFrameId < 0 ) {
+    if ( requestType === 'doc' && details.parentFrameId === -1 ) {
         return onBeforeRootFrameRequestHandler(details);
     }
 
-    var requestURL = details.url;
+    var µm = µMatrix,
+        µmuri = µm.URI,
+        requestURL = details.url,
+        requestScheme = µmuri.schemeFromURI(requestURL);
 
     // Ignore non-network schemes
     if ( µmuri.isNetworkScheme(requestScheme) === false ) {
@@ -109,13 +102,24 @@ var onBeforeRequestHandler = function(details) {
     // to scope on unknown scheme? Etc.
     // https://github.com/gorhill/httpswitchboard/issues/191
     // https://github.com/gorhill/httpswitchboard/issues/91#issuecomment-37180275
-    var tabContext = µm.tabContextManager.mustLookup(details.tabId);
-    var tabId = tabContext.tabId;
-    var rootHostname = tabContext.rootHostname;
+    var tabContext = µm.tabContextManager.mustLookup(details.tabId),
+        tabId = tabContext.tabId,
+        rootHostname = tabContext.rootHostname,
+        specificity = 0;
+
+    // Filter through matrix
+    var block = µm.tMatrix.mustBlock(
+        rootHostname,
+        µmuri.hostnameFromURI(requestURL),
+        requestType
+    );
+    if ( block ) {
+        specificity = µm.tMatrix.specificityRegister;
+    }
 
     // Enforce strict secure connection?
-    var block = false;
     if (
+        block === false &&
         tabContext.secure &&
         µmuri.isSecureScheme(requestScheme) === false &&
         µm.tMatrix.evaluateSwitchZ('https-strict', rootHostname)
@@ -123,11 +127,6 @@ var onBeforeRequestHandler = function(details) {
         block = true;
     }
 
-    // Disallow request as per temporary matrix?
-    if ( block === false ) {
-        block = µm.mustBlock(rootHostname, µmuri.hostnameFromURI(requestURL), requestType);
-    }
-
     // Record request.
     // https://github.com/gorhill/httpswitchboard/issues/342
     // The way requests are handled now, it may happen at this point some
@@ -138,16 +137,10 @@ var onBeforeRequestHandler = function(details) {
     pageStore.recordRequest(requestType, requestURL, block);
     µm.logger.writeOne(tabId, 'net', rootHostname, requestURL, details.type, block);
 
-    // Allowed?
-    if ( !block ) {
-        // console.debug('onBeforeRequestHandler()> ALLOW "%s": %o', details.url, details);
-        return;
+    if ( block ) {
+        pageStore.cacheBlockedCollapsible(requestType, requestURL, specificity);
+        return { 'cancel': true };
     }
-
-    // Blocked
-    // console.debug('onBeforeRequestHandler()> BLOCK "%s": %o', details.url, details);
-
-    return { 'cancel': true };
 };
 
 /******************************************************************************/
diff --git a/src/settings.html b/src/settings.html
index 1c14b2e..f162596 100644
--- a/src/settings.html
+++ b/src/settings.html
@@ -33,17 +33,17 @@ ul > li.separator {
 
 <h2 data-i18n="settingsMatrixConvenienceHeader"></h2>
 <ul>
-    <li>
-        <input id="iconBadgeEnabled" type="checkbox" data-setting-bool="iconBadgeEnabled">
+    <li><input id="iconBadgeEnabled" type="checkbox" data-setting-bool>
         <label data-i18n="settingsIconBadgeEnabled" for="iconBadgeEnabled"></label>
-    <li>
-        <input id="collapseBlocked" type="checkbox" data-setting-bool="collapseBlocked">
+    <li><input id="collapseBlocked" type="checkbox" data-setting-bool>
         <label data-i18n="settingsCollapseBlocked" for="collapseBlocked"></label>
-    <li>
-        <input id="noscriptTagsSpoofed" type="checkbox" data-matrix-switch="noscript-spoof">
+        <ul>
+            <li><input id="collapseBlacklisted" type="checkbox" data-setting-bool>
+                <label data-i18n="settingsCollapseBlacklisted" for="collapseBlacklisted"></label>
+        </ul>
+    <li><input id="noscriptTagsSpoofed" type="checkbox" data-matrix-switch="noscript-spoof">
         <label data-i18n="settingsNoscriptTagsSpoofed" for="noscriptTagsSpoofed"></label>
-    <li>
-        <input id="cloudStorageEnabled" type="checkbox" data-setting-bool="cloudStorageEnabled">
+    <li><input id="cloudStorageEnabled" type="checkbox" data-setting-bool>
         <label data-i18n="settingsCloudStorageEnabled" for="cloudStorageEnabled"></label>
 </ul>
 <h2 data-i18n="settingsMatrixDisplayHeader"></h2>
@@ -56,18 +56,18 @@ ul > li.separator {
         <label data-i18n="settingsDefaultScopeLevel"></label> <select id="popupScopeLevel"><option data-i18n="settingsDefaultScopeLevel2" value="site"><option data-i18n="settingsDefaultScopeLevel1" value="domain"><option data-i18n="settingsDefaultScopeLevel0" value="*"></select>
     <li class="separator">
     <li>
-        <input id="colorBlindFriendly" type="checkbox" data-setting-bool="colorBlindFriendly">
+        <input id="colorBlindFriendly" type="checkbox" data-setting-bool>
         <label data-i18n="settingsMatrixDisplayColorBlind" for="colorBlindFriendly"></label>
 </ul>
 <h2 data-i18n="privacyPageName"></h2>
 <ul>
     <li>
-        <input id="delete-blacklisted-cookies" type="checkbox" data-setting-bool="deleteCookies"><label data-i18n="privacyDeleteBlockedCookiesPrompt" for="delete-blacklisted-cookies"></label>
+        <input id="deleteCookies" type="checkbox" data-setting-bool><label data-i18n="privacyDeleteBlockedCookiesPrompt" for="deleteCookies"></label>
         <span class="whatisthis"></span>
         <div class="whatisthis-expandable para" data-i18n="privacyDeleteBlockedCookiesHelp"></div>
     <li>
-        <input id="delete-unused-session-cookies" type="checkbox" data-setting-bool="deleteUnusedSessionCookies"><label data-i18n="privacyDeleteNonBlockedSessionCookiesPrompt1" for="delete-unused-session-cookies"></label>
-        <input id="delete-unused-session-cookies-after" type="text" value="60" size="3"><span data-i18n="privacyDeleteNonBlockedSessionCookiesPrompt2"></span>
+        <input id="deleteUnusedSessionCookies" type="checkbox" data-setting-bool><label data-i18n="privacyDeleteNonBlockedSessionCookiesPrompt1" for="deleteUnusedSessionCookies"></label>
+        <input id="deleteUnusedSessionCookiesAfter" type="text" value="60" size="3"><span data-i18n="privacyDeleteNonBlockedSessionCookiesPrompt2"></span>
         <span class="whatisthis"></span>
         <div class="whatisthis-expandable para" data-i18n="privacyDeleteNonBlockedSessionCookiesHelp"></div>
     <!--
@@ -89,22 +89,22 @@ ul > li.separator {
         of these cookies so that they cannot be used to track you.
     -->
     <li>
-        <input id="delete-blacklisted-localstorage" type="checkbox" data-setting-bool="deleteLocalStorage"><label data-i18n="privacyDeleteBlockedLocalStoragePrompt" for="delete-blacklisted-localstorage"></label>
+        <input id="deleteLocalStorage" type="checkbox" data-setting-bool><label data-i18n="privacyDeleteBlockedLocalStoragePrompt" for="deleteLocalStorage"></label>
     <li>
-        <input id="clear-browser-cache" type="checkbox" data-setting-bool="clearBrowserCache"><label data-i18n="privacyClearCachePrompt1" for="clear-browser-cache"></label> 
-        <input id="clear-browser-cache-after" type="text" value="60" size="3"> <label data-i18n="privacyClearCachePrompt2" for="clear-browser-cache-after"></label>
+        <input id="clearBrowserCache" type="checkbox" data-setting-bool><label data-i18n="privacyClearCachePrompt1" for="clearBrowserCache"></label> 
+        <input id="clearBrowserCacheAfter" type="text" value="60" size="3"> <label data-i18n="privacyClearCachePrompt2" for="clearBrowserCacheAfter"></label>
         <span class="whatisthis"></span>
         <div class="whatisthis-expandable para" data-i18n="privacyClearCacheHelp"></div>
     <li>
-        <input id="process-referer" type="checkbox" data-matrix-switch="referrer-spoof"><label data-i18n="privacyProcessRefererPrompt" for="process-referer"></label>
+        <input id="processReferer" type="checkbox" data-matrix-switch="referrer-spoof"><label data-i18n="privacyProcessRefererPrompt" for="processReferer"></label>
         <span class="whatisthis"></span>
         <div class="whatisthis-expandable para" data-i18n="privacyProcessRefererHelp"></div>
     <li>
-        <input id="no-mixed-content" type="checkbox" data-matrix-switch="https-strict"><label data-i18n="privacyNoMixedContentPrompt" for="no-mixed-content"></label>
+        <input id="noMixedContent" type="checkbox" data-matrix-switch="https-strict"><label data-i18n="privacyNoMixedContentPrompt" for="noMixedContent"></label>
         <span class="whatisthis"></span>
         <div class="whatisthis-expandable para" data-i18n="privacyNoMixedContentHelp"></div>
     <li>
-        <input id="process-hyperlink-auditing" type="checkbox" data-setting-bool="processHyperlinkAuditing"><label data-i18n="privacyProcessHyperlinkAuditingPrompt" for="process-hyperlink-auditing"></label>
+        <input id="processHyperlinkAuditing" type="checkbox" data-setting-bool><label data-i18n="privacyProcessHyperlinkAuditingPrompt" for="processHyperlinkAuditing"></label>
         <span class="whatisthis"></span>
         <div class="whatisthis-expandable para" data-i18n="privacyProcessHyperlinkAuditingHelp"></div>
 </ul>