diff --git a/platform/common/vapi-background.js b/platform/common/vapi-background.js
index d57628849..aa60cda58 100644
--- a/platform/common/vapi-background.js
+++ b/platform/common/vapi-background.js
@@ -1191,7 +1191,7 @@ vAPI.Net = class {
         this.deferredSuspendableListener = undefined;
         this.listenerMap = new WeakMap();
         this.suspendDepth = 0;
-        this.unprocessedTabs = new Set();
+        this.unprocessedTabs = new Map();
 
         browser.webRequest.onBeforeRequest.addListener(
             details => {
@@ -1252,6 +1252,17 @@ vAPI.Net = class {
         this.onUnprocessedRequest(details);
     }
     setSuspendableListener(listener) {
+        for ( const [ tabId, requests ] of this.unprocessedTabs ) {
+            let i = requests.length;
+            while ( i-- ) {
+                const r = listener(requests[i]);
+                if ( r === undefined || r.cancel === false ) {
+                    requests.splice(i, 1);
+                }
+            }
+            if ( requests.length !== 0 ) { continue; }
+            this.unprocessedTabs.delete(tabId);
+        }
         if ( this.unprocessedTabs.size !== 0 ) {
             this.deferredSuspendableListener = listener;
             listener = details => {
@@ -1285,11 +1296,16 @@ vAPI.Net = class {
         return actualListener;
     }
     onUnprocessedRequest(details) {
-        if ( details.tabId === -1 ) { return; }
+        const { tabId } = details;
+        if ( tabId === -1 ) { return; }
         if ( this.unprocessedTabs.size === 0 ) {
             vAPI.setDefaultIcon('-loading', '!');
         }
-        this.unprocessedTabs.add(details.tabId);
+        let requests = this.unprocessedTabs.get(tabId);
+        if ( requests === undefined ) {
+            this.unprocessedTabs.set(tabId, (requests = []));
+        }
+        requests.push(Object.assign({}, details));
     }
     hasUnprocessedRequest(tabId) {
         return this.unprocessedTabs.size !== 0 &&
diff --git a/src/js/start.js b/src/js/start.js
index 6565e916e..abf54e96e 100644
--- a/src/js/start.js
+++ b/src/js/start.js
@@ -103,6 +103,7 @@ const initializeTabs = async ( ) => {
         const tabs = await vAPI.tabs.query({ url: '<all_urls>' });
         for ( const tab of tabs  ) {
             if ( tab.discarded === true ) { continue; }
+            if ( tab.status === 'unloaded' ) { continue; }
             const { id, url } = tab;
             µb.tabContextManager.commit(id, url);
             µb.bindTabToPageStore(id, 'tabCommitted', tab);
@@ -118,21 +119,23 @@ const initializeTabs = async ( ) => {
             tabIds.push(id);
         }
     }
-    const results = await Promise.all(toCheck);
-    for ( let i = 0; i < results.length; i++ ) {
-        const result = results[i];
-        if ( result.length === 0 || result[0] !== true ) { continue; }
-        // Inject declarative content scripts programmatically.
-        for ( const contentScript of manifest.content_scripts ) {
-            for ( const file of contentScript.js ) {
-                vAPI.tabs.executeScript(tabIds[i], {
-                    file: file,
-                    allFrames: contentScript.all_frames,
-                    runAt: contentScript.run_at
-                });
+    // We do not want to block on content scripts injection
+    Promise.all(toCheck).then(results => {
+        for ( let i = 0; i < results.length; i++ ) {
+            const result = results[i];
+            if ( result.length === 0 || result[0] !== true ) { continue; }
+            // Inject declarative content scripts programmatically.
+            for ( const contentScript of manifest.content_scripts ) {
+                for ( const file of contentScript.js ) {
+                    vAPI.tabs.executeScript(tabIds[i], {
+                        file: file,
+                        allFrames: contentScript.all_frames,
+                        runAt: contentScript.run_at
+                    });
+                }
             }
         }
-    }
+    });
 };
 
 /******************************************************************************/
@@ -462,6 +465,9 @@ if ( selfieIsValid !== true ) {
 //   This can be used to defer filtering decision-making.
 µb.readyToFilter = true;
 
+// Initialize internal state with maybe already existing tabs.
+await initializeTabs();
+
 // Start network observers.
 webRequest.start();
 
@@ -472,9 +478,6 @@ webRequest.start();
 // as possible ensure minimal memory usage baseline.
 lz4Codec.relinquish();
 
-// Initialize internal state with maybe already existing tabs.
-initializeTabs();
-
 // https://github.com/chrisaljoudi/uBlock/issues/184
 //   Check for updates not too far in the future.
 io.addObserver(µb.assetObserver.bind(µb));