diff --git a/src/js/cosmetic-filtering.js b/src/js/cosmetic-filtering.js
index d8534c49b..f9c1a79a1 100644
--- a/src/js/cosmetic-filtering.js
+++ b/src/js/cosmetic-filtering.js
@@ -204,6 +204,9 @@ const FilterContainer = function() {
     // specific filters
     this.specificFilters = new µb.staticExtFilteringEngine.HostnameBasedDB(2);
 
+    // temporary filters
+    this.sessionFilterDB = new µb.staticExtFilteringEngine.SessionDB();
+
     // low generic cosmetic filters, organized by id/class then simple/complex.
     this.lowlyGeneric = Object.create(null);
     this.lowlyGeneric.id = {
@@ -827,7 +830,7 @@ FilterContainer.prototype.randomAlphaToken = function() {
 /******************************************************************************/
 
 FilterContainer.prototype.getSession = function() {
-    return this.specificFilters.session;
+    return this.sessionFilterDB;
 };
 
 /******************************************************************************/
@@ -997,7 +1000,9 @@ FilterContainer.prototype.retrieveSpecificSelectors = function(
         }
 
         // Retrieve temporary filters
-        this.specificFilters.session.retrieve([ dummySet, exceptionSet ]);
+        if ( this.sessionFilterDB.isNotEmpty ) {
+            this.sessionFilterDB.retrieve([ null, exceptionSet ]);
+        }
 
         // Retrieve filters with a non-empty hostname
         this.specificFilters.retrieve(
diff --git a/src/js/html-filtering.js b/src/js/html-filtering.js
index 9d7c8c19d..338d5e18d 100644
--- a/src/js/html-filtering.js
+++ b/src/js/html-filtering.js
@@ -28,10 +28,11 @@
     const pselectors = new Map();
     const duplicates = new Set();
 
-    let filterDB = new µb.staticExtFilteringEngine.HostnameBasedDB(2),
-        acceptedCount = 0,
-        discardedCount = 0,
-        docRegister;
+    const filterDB = new µb.staticExtFilteringEngine.HostnameBasedDB(2);
+    const sessionFilterDB = new µb.staticExtFilteringEngine.SessionDB();
+    let acceptedCount = 0;
+    let discardedCount = 0;
+    let docRegister;
 
     const api = {
         get acceptedCount() {
@@ -335,7 +336,7 @@
     };
 
     api.getSession = function() {
-        return filterDB.session;
+        return sessionFilterDB;
     };
 
     api.retrieve = function(details) {
@@ -354,7 +355,9 @@
         const procedurals = new Set();
         const exceptions = new Set();
 
-        filterDB.session.retrieve([ new Set(), exceptions ]);
+        if ( sessionFilterDB.isNotEmpty ) {
+            sessionFilterDB.retrieve([ null, exceptions ]);
+        }
         filterDB.retrieve(
             hostname,
             [ plains, exceptions, procedurals, exceptions ]
@@ -415,7 +418,7 @@
     };
 
     api.fromSelfie = function(selfie) {
-        filterDB = new µb.staticExtFilteringEngine.HostnameBasedDB(2, selfie);
+        filterDB.fromSelfie(selfie);
         pselectors.clear();
     };
 
diff --git a/src/js/logger-ui.js b/src/js/logger-ui.js
index 400883189..6736de2ed 100644
--- a/src/js/logger-ui.js
+++ b/src/js/logger-ui.js
@@ -1451,14 +1451,11 @@ const reloadTab = function(ev) {
         span.className = 'filter';
         span.textContent = selector;
         fragment.appendChild(span);
-        let isTemporaryException = false;
-        if ( match[0] === '#@#' ) {
-            isTemporaryException = await messaging.send('loggerUI', {
-                what: 'hasTemporaryException',
-                filter,
-            });
-            receiver.classList.toggle('exceptored', isTemporaryException);
-        }
+        const isTemporaryException = await messaging.send('loggerUI', {
+            what: 'hasTemporaryException',
+            filter,
+        });
+        receiver.classList.toggle('exceptored', isTemporaryException);
         if ( match[0] === '##' || isTemporaryException ) {
             receiver.children[2].style.visibility = '';
         }
diff --git a/src/js/scriptlet-filtering.js b/src/js/scriptlet-filtering.js
index e83c44e90..29a630dc5 100644
--- a/src/js/scriptlet-filtering.js
+++ b/src/js/scriptlet-filtering.js
@@ -24,14 +24,15 @@
 /******************************************************************************/
 
 µBlock.scriptletFilteringEngine = (function() {
-    const µb = µBlock,
-        duplicates = new Set(),
-        scriptletCache = new µb.MRUCache(32),
-        reEscapeScriptArg = /[\\'"]/g;
+    const µb = µBlock;
+    const duplicates = new Set();
+    const scriptletCache = new µb.MRUCache(32);
+    const reEscapeScriptArg = /[\\'"]/g;
 
-    let acceptedCount = 0,
-        discardedCount = 0,
-        scriptletDB = new µb.staticExtFilteringEngine.HostnameBasedDB(1);
+    const scriptletDB = new µb.staticExtFilteringEngine.HostnameBasedDB(1);
+    const sessionScriptletDB = new µb.staticExtFilteringEngine.SessionDB();
+    let acceptedCount = 0;
+    let discardedCount = 0;
 
     const api = {
         get acceptedCount() {
@@ -343,7 +344,7 @@
     };
 
     api.getSession = function() {
-        return scriptletDB.session;
+        return sessionScriptletDB;
     };
 
     const scriptlets$ = new Set();
@@ -371,7 +372,9 @@
         scriptlets$.clear();
         exceptions$.clear();
 
-        scriptletDB.session.retrieve([ scriptlets$, exceptions$ ]);
+        if ( sessionScriptletDB.isNotEmpty ) {
+            sessionScriptletDB.retrieve([ null, exceptions$ ]);
+        }
         scriptletDB.retrieve(hostname, [ scriptlets$, exceptions$ ]);
         if ( request.entity !== '' ) {
             scriptletDB.retrieve(
@@ -464,7 +467,7 @@
     };
 
     api.fromSelfie = function(selfie) {
-        scriptletDB = new µb.staticExtFilteringEngine.HostnameBasedDB(1, selfie);
+        scriptletDB.fromSelfie(selfie);
     };
 
     api.benchmark = async function() {
diff --git a/src/js/static-ext-filtering.js b/src/js/static-ext-filtering.js
index 53da1919d..087f2da07 100644
--- a/src/js/static-ext-filtering.js
+++ b/src/js/static-ext-filtering.js
@@ -511,7 +511,6 @@
     //--------------------------------------------------------------------------
 
     api.HostnameBasedDB = class {
-
         constructor(nBits, selfie = undefined) {
             this.nBits = nBits;
             this.timer = undefined;
@@ -524,41 +523,6 @@
             // Array of strings (selectors and pseudo-selectors)
             this.strSlots = [];
             this.size = 0;
-            // Temporary set
-            this.session = {
-                collection: new Map(),
-                add: function(bits, s) {
-                    const bucket = this.collection.get(bits);
-                    if ( bucket === undefined ) {
-                        this.collection.set(bits, new Set([ s ]));
-                    } else {
-                        bucket.add(s);
-                    }
-                },
-                remove: function(bits, s) {
-                    const bucket = this.collection.get(bits);
-                    if ( bucket === undefined ) { return; }
-                    bucket.delete(s);
-                    if ( bucket.size !== 0 ) { return; }
-                    this.collection.delete(bits);
-                },
-                retrieve(out) {
-                    const mask = out.length - 1;
-                    for ( const [ bits, bucket ] of this.collection ) {
-                        for ( const s of bucket ) {
-                            out[bits & mask].add(s);
-                        }
-                    }
-                },
-                has(bits, s) {
-                    const selectors = this.collection.get(bits);
-                    return selectors !== undefined && selectors.has(s);
-                },
-                clear() {
-                    this.collection.clear();
-                },
-            };
-
             if ( selfie !== undefined ) {
                 this.fromSelfie(selfie);
             }
@@ -675,6 +639,47 @@
         }
     };
 
+    api.SessionDB = class {
+        constructor() {
+            this.db = new Map();
+        }
+        add(bits, s) {
+            const bucket = this.db.get(bits);
+            if ( bucket === undefined ) {
+                this.db.set(bits, new Set([ s ]));
+            } else {
+                bucket.add(s);
+            }
+        }
+        remove(bits, s) {
+            const bucket = this.db.get(bits);
+            if ( bucket === undefined ) { return; }
+            bucket.delete(s);
+            if ( bucket.size !== 0 ) { return; }
+            this.db.delete(bits);
+        }
+        retrieve(out) {
+            const mask = out.length - 1;
+            for ( const [ bits, bucket ] of this.db ) {
+                const i = bits & mask;
+                if ( out[i] instanceof Object === false ) { continue; }
+                for ( const s of bucket ) {
+                    out[i].add(s);
+                }
+            }
+        }
+        has(bits, s) {
+            const selectors = this.db.get(bits);
+            return selectors !== undefined && selectors.has(s);
+        }
+        clear() {
+            this.db.clear();
+        }
+        get isNotEmpty() {
+            return this.db.size !== 0;
+        }
+    };
+
     //--------------------------------------------------------------------------
     // Public methods
     //--------------------------------------------------------------------------