diff --git a/devtools/client/aboutdebugging/test/browser_service_workers.js b/devtools/client/aboutdebugging/test/browser_service_workers.js
index ff084063e632..c5f69c993de5 100644
--- a/devtools/client/aboutdebugging/test/browser_service_workers.js
+++ b/devtools/client/aboutdebugging/test/browser_service_workers.js
@@ -13,7 +13,7 @@ add_task(function* () {
 
   let { tab, document } = yield openAboutDebugging("workers");
 
-  let swTab = yield addTab(TAB_URL);
+  let swTab = yield addTab(TAB_URL, { background: true });
 
   let serviceWorkersElement = getServiceWorkerList(document);
 
diff --git a/devtools/client/aboutdebugging/test/browser_service_workers_fetch_flag.js b/devtools/client/aboutdebugging/test/browser_service_workers_fetch_flag.js
index c1bb720c4e3c..91392a9d3d5e 100644
--- a/devtools/client/aboutdebugging/test/browser_service_workers_fetch_flag.js
+++ b/devtools/client/aboutdebugging/test/browser_service_workers_fetch_flag.js
@@ -12,7 +12,7 @@ function* testBody(url, expecting) {
   yield enableServiceWorkerDebugging();
   let { tab, document } = yield openAboutDebugging("workers");
 
-  let swTab = yield addTab(url);
+  let swTab = yield addTab(url, {background: true});
 
   let serviceWorkersElement = getServiceWorkerList(document);
 
diff --git a/devtools/client/aboutdebugging/test/browser_service_workers_push.js b/devtools/client/aboutdebugging/test/browser_service_workers_push.js
index 087e0c535263..206a71601904 100644
--- a/devtools/client/aboutdebugging/test/browser_service_workers_push.js
+++ b/devtools/client/aboutdebugging/test/browser_service_workers_push.js
@@ -22,7 +22,7 @@ add_task(function* () {
   let serviceWorkersElement = getServiceWorkerList(document);
 
   // Open a tab that registers a push service worker.
-  let swTab = yield addTab(TAB_URL);
+  let swTab = yield addTab(TAB_URL, { background: true });
 
   info("Make the test page notify us when the service worker sends a message.");
 
diff --git a/devtools/client/aboutdebugging/test/browser_service_workers_push_service.js b/devtools/client/aboutdebugging/test/browser_service_workers_push_service.js
index f29236130bde..c10c29377bd2 100644
--- a/devtools/client/aboutdebugging/test/browser_service_workers_push_service.js
+++ b/devtools/client/aboutdebugging/test/browser_service_workers_push_service.js
@@ -58,7 +58,7 @@ add_task(function* () {
   let serviceWorkersElement = document.getElementById("service-workers");
 
   // Open a tab that registers a push service worker.
-  let swTab = yield addTab(TAB_URL);
+  let swTab = yield addTab(TAB_URL, { background: true });
 
   info("Wait until the service worker appears in about:debugging");
   yield waitUntilServiceWorkerContainer(SERVICE_WORKER, document);
diff --git a/devtools/client/aboutdebugging/test/browser_service_workers_start.js b/devtools/client/aboutdebugging/test/browser_service_workers_start.js
index 1dda465dff7a..5ad1be73fc69 100644
--- a/devtools/client/aboutdebugging/test/browser_service_workers_start.js
+++ b/devtools/client/aboutdebugging/test/browser_service_workers_start.js
@@ -25,7 +25,7 @@ add_task(function* () {
   let serviceWorkersElement = getServiceWorkerList(document);
 
   // Open a tab that registers an empty service worker.
-  let swTab = yield addTab(TAB_URL);
+  let swTab = yield addTab(TAB_URL, { background: true });
 
   // Wait for the service-workers list to update.
   info("Wait until the service worker appears in about:debugging");
diff --git a/devtools/client/aboutdebugging/test/browser_service_workers_status.js b/devtools/client/aboutdebugging/test/browser_service_workers_status.js
index e5912385a1ae..d5d41a57c34c 100644
--- a/devtools/client/aboutdebugging/test/browser_service_workers_status.js
+++ b/devtools/client/aboutdebugging/test/browser_service_workers_status.js
@@ -21,7 +21,7 @@ add_task(function* () {
   // Listen for mutations in the service-workers list.
   let serviceWorkersElement = getServiceWorkerList(document);
 
-  let swTab = yield addTab(TAB_URL);
+  let swTab = yield addTab(TAB_URL, { background: true });
 
   info("Wait until the service worker appears in about:debugging");
   let container = yield waitUntilServiceWorkerContainer(SERVICE_WORKER, document);
diff --git a/devtools/client/aboutdebugging/test/browser_service_workers_timeout.js b/devtools/client/aboutdebugging/test/browser_service_workers_timeout.js
index d2505f848ba9..2495b454d91a 100644
--- a/devtools/client/aboutdebugging/test/browser_service_workers_timeout.js
+++ b/devtools/client/aboutdebugging/test/browser_service_workers_timeout.js
@@ -20,7 +20,7 @@ add_task(function* () {
 
   let serviceWorkersElement = getServiceWorkerList(document);
 
-  let swTab = yield addTab(TAB_URL);
+  let swTab = yield addTab(TAB_URL, { background: true });
 
   info("Wait until the service worker appears in about:debugging");
   yield waitUntilServiceWorkerContainer(SERVICE_WORKER, document);
diff --git a/devtools/client/aboutdebugging/test/browser_service_workers_unregister.js b/devtools/client/aboutdebugging/test/browser_service_workers_unregister.js
index 276325c8ac5e..b846d9e6d353 100644
--- a/devtools/client/aboutdebugging/test/browser_service_workers_unregister.js
+++ b/devtools/client/aboutdebugging/test/browser_service_workers_unregister.js
@@ -20,7 +20,7 @@ add_task(function* () {
   let { tab, document } = yield openAboutDebugging("workers");
 
   // Open a tab that registers an empty service worker.
-  let swTab = yield addTab(TAB_URL);
+  let swTab = yield addTab(TAB_URL, { background: true });
 
   info("Wait until the service worker appears in about:debugging");
   yield waitUntilServiceWorkerContainer(SERVICE_WORKER, document);