diff --git a/js/messaging-handlers.js b/js/messaging-handlers.js
index 5c061865c..727645c27 100644
--- a/js/messaging-handlers.js
+++ b/js/messaging-handlers.js
@@ -202,6 +202,8 @@ var tagNameToRequestTypeMap = {
 
 var filterRequests = function(pageStore, details) {
     details.pageDomain = µb.URI.domainFromHostname(details.pageHostname);
+    details.rootHostname = pageStore.rootHostname;
+    details.rootDomain = pageStore.rootDomain;
 
     var inRequests = details.requests;
     var outRequests = [];
@@ -236,6 +238,8 @@ var filterRequest = function(pageStore, details) {
         return;
     }
     details.pageDomain = µb.URI.domainFromHostname(details.pageHostname);
+    details.rootHostname = pageStore.rootHostname;
+    details.rootDomain = pageStore.rootDomain;
     var result = pageStore.filterRequest(
         details,
         tagNameToRequestTypeMap[details.tagName],
diff --git a/js/net-filtering.js b/js/net-filtering.js
index 68680eee9..342bf4e85 100644
--- a/js/net-filtering.js
+++ b/js/net-filtering.js
@@ -140,6 +140,15 @@ var atoi = function(s) {
     return cachedParseInt(s, 10);
 };
 
+var isFirstParty = function(firstPartyDomain, hostname) {
+    if ( hostname.slice(0 - firstPartyDomain.length) !== firstPartyDomain ) {
+        return false;
+    }
+    // Be sure to not confuse 'example.com' with 'anotherexample.com'
+    var c = hostname.charAt(hostname.length - firstPartyDomain.length - 1);
+    return c === '.' || c === '';
+};
+
 /*******************************************************************************
 
 Filters family tree:
@@ -1945,19 +1954,21 @@ FilterContainer.prototype.match3rdPartyHostname = function(requestHostname) {
 
 FilterContainer.prototype.matchStringExactType = function(pageDetails, requestURL, requestType) {
     var url = requestURL.toLowerCase();
-    var pageDomain = pageDetails.pageDomain || '';
     var requestHostname = µb.URI.hostnameFromURI(requestURL);
-    var party = requestHostname.slice(-pageDomain.length) === pageDomain ?
-        FirstParty :
-        ThirdParty;
 
     // Evaluate dynamic filters first. "Block" dynamic filters are always
     // "important", they override everything else.
-    var bf = this.matchDynamicFilters(pageDetails.rootHostname, requestType, party === FirstParty);
+    var bf = this.matchDynamicFilters(
+        pageDetails.rootHostname,
+        requestType,
+        isFirstParty(pageDetails.rootDomain, requestHostname)
+    );
     if ( bf !== '' && bf.slice(0, 2) !== '@@' ) {
         return bf;
     }
 
+    var party = isFirstParty(pageDetails.pageDomain, requestHostname) ? FirstParty : ThirdParty;
+
     // This will be used by hostname-based filters
     pageHostname = pageDetails.pageHostname || '';
 
@@ -2030,26 +2041,21 @@ FilterContainer.prototype.matchString = function(pageDetails, requestURL, reques
     // filters are tested *only* if there is a (unlikely) hit on a block
     // filter.
 
-    var pageDomain = pageDetails.pageDomain || '';
     var requestHostname = µb.URI.hostnameFromURI(requestURL);
 
-    // Find out the relation between the page and request
-    var party = ThirdParty;
-    if ( requestHostname.slice(0 - pageDomain.length) === pageDomain ) {
-        // Be sure to not confuse 'example.com' with 'anotherexample.com'
-        var c = requestHostname.charAt(requestHostname.length - pageDomain.length - 1);
-        if ( c === '' || c === '.' ) {
-            party = FirstParty;
-        }
-    }
-
     // Evaluate dynamic filters first. "Block" dynamic filters are always
     // "important", they override everything else.
-    var bf = this.matchDynamicFilters(pageDetails.rootHostname, requestType, party === FirstParty);
+    var bf = this.matchDynamicFilters(
+        pageDetails.rootHostname,
+        requestType,
+        isFirstParty(pageDetails.rootDomain, requestHostname)
+    );
     if ( bf !== '' && bf.slice(0, 2) !== '@@' ) {
         return bf;
     }
 
+    var party = isFirstParty(pageDetails.pageDomain, requestHostname) ? FirstParty : ThirdParty ;
+
     // This will be used by hostname-based filters
     pageHostname = pageDetails.pageHostname || '';
 
diff --git a/js/pagestore.js b/js/pagestore.js
index ddd2940d2..6d8b73788 100644
--- a/js/pagestore.js
+++ b/js/pagestore.js
@@ -240,15 +240,17 @@ FrameStore.factory = function(rootHostname, frameURL) {
 FrameStore.prototype.init = function(rootHostname, frameURL) {
     var µburi = µb.URI;
     this.pageHostname = µburi.hostnameFromURI(frameURL);
-    this.pageDomain = µburi.domainFromHostname(this.pageHostname);
+    this.pageDomain = µburi.domainFromHostname(this.pageHostname) || this.pageHostname;
     this.rootHostname = rootHostname;
+    this.rootDomain = µburi.domainFromHostname(rootHostname) || rootHostname;
     return this;
 };
 
 /******************************************************************************/
 
 FrameStore.prototype.dispose = function() {
-    this.pageHostname = this.pageDomain = this.rootHostname = '';
+    this.pageHostname = this.pageDomain =
+    this.rootHostname = this.rootDomain = '';
     if ( frameStoreJunkyard.length < frameStoreJunkyardMax ) {
         frameStoreJunkyard.push(this);
     }
@@ -298,6 +300,7 @@ PageStore.prototype.init = function(tabId, pageURL) {
     // Use hostname if no domain can be extracted
     this.pageDomain = µb.URI.domainFromHostname(this.pageHostname) || this.pageHostname;
     this.rootHostname = this.pageHostname;
+    this.rootDomain = this.pageDomain;
 
     this.frames = {};
     this.netFiltering = true;
@@ -327,6 +330,7 @@ PageStore.prototype.reuse = function(pageURL, context) {
         this.pageHostname = µb.URI.hostnameFromURI(pageURL);
         this.pageDomain = µb.URI.domainFromHostname(this.pageHostname) || this.pageHostname;
         this.rootHostname = this.pageHostname;
+        this.rootDomain = this.pageDomain;
         return this;
     }
     // A new page is completely reloaded from scratch, reset all.
@@ -347,11 +351,9 @@ PageStore.prototype.dispose = function() {
     // need to release the memory taken by these, which can amount to
     // sizeable enough chunks (especially requests, through the request URL
     // used as a key).
-    this.pageURL = '';
-    this.previousPageURL = '';
-    this.pageHostname = '';
-    this.pageDomain = '';
-    this.rootHostname = '';
+    this.pageURL = this.previousPageURL =
+    this.pageHostname = this.pageDomain = 
+    this.rootHostname = this.rootDomain = '';
     this.disposeFrameStores();
     this.netFilteringCache = this.netFilteringCache.dispose();
     if ( pageStoreJunkyard.length < pageStoreJunkyardMax ) {