diff --git a/platform/webext/manifest.json b/platform/webext/manifest.json
index 1d2954238..c9fd692d3 100644
--- a/platform/webext/manifest.json
+++ b/platform/webext/manifest.json
@@ -33,7 +33,8 @@
       {
          "matches":[
             "http://*/*",
-            "https://*/*"
+            "https://*/*",
+            "file://*/*"
          ],
          "js":[
             "js/vapi-client.js",
diff --git a/src/js/contentscript.js b/src/js/contentscript.js
index 8a22379e9..5838b4dde 100644
--- a/src/js/contentscript.js
+++ b/src/js/contentscript.js
@@ -1114,20 +1114,10 @@ vAPI.domCollapser = (function() {
     var send = function() {
         processTimer = undefined;
         toCollapse.set(resquestIdGenerator, toProcess);
-        // https://github.com/gorhill/uBlock/issues/1927
-        //   Normalize hostname to avoid trailing dot of FQHN.
-        var pageHostname = window.location.hostname || '';
-        if (
-            pageHostname.length &&
-            pageHostname.charCodeAt(pageHostname.length - 1) === 0x2e
-        ) {
-            pageHostname = pageHostname.slice(0, -1);
-        }
         var msg = {
             what: 'getCollapsibleBlockedRequests',
             id: resquestIdGenerator,
-            pageURL: window.location.href,
-            pageHostname: pageHostname,
+            frameURL: window.location.href,
             resources: toFilter,
             hash: cachedBlockedSetHash
         };
diff --git a/src/js/pagestore.js b/src/js/pagestore.js
index 429d8bd91..cbac482ea 100644
--- a/src/js/pagestore.js
+++ b/src/js/pagestore.js
@@ -699,21 +699,26 @@ PageStore.prototype.filterLargeMediaElement = function(size) {
 /******************************************************************************/
 
 PageStore.prototype.getBlockedResources = function(request, response) {
-    var resources = request.resources;
+    var µburi = µb.URI,
+        normalURL = µb.normalizePageURL(this.tabId, request.frameURL),
+        frameHostname = µburi.hostnameFromURI(normalURL),
+        resources = request.resources;
+    // Force some resources to go through the filtering engine in order to
+    // populate the blocked-resources cache. This is required because for
+    // some resources it's not possible to detect whether they were blocked
+    // content script-side (i.e. `iframes` -- unlike `img`).
     if ( Array.isArray(resources) && resources.length !== 0 ) {
-        var context = this.createContextFromFrameHostname(request.pageHostname);
+        var context = this.createContextFromFrameHostname(frameHostname);
         for ( var resource of resources ) {
             context.requestType = resource.type;
-            context.requestHostname = µb.URI.hostnameFromURI(resource.url);
+            context.requestHostname = µburi.hostnameFromURI(resource.url);
             context.requestURL = resource.url;
             this.filterRequest(context);
         }
     }
-    if ( this.netFilteringCache.hash === response.hash ) {
-        return;
-    }
+    if ( this.netFilteringCache.hash === response.hash ) { return; }
     response.hash = this.netFilteringCache.hash;
-    response.blockedResources = this.netFilteringCache.lookupAllBlocked(request.pageHostname);
+    response.blockedResources = this.netFilteringCache.lookupAllBlocked(frameHostname);
 };
 
 /******************************************************************************/