diff --git a/spec-main/fixtures/devtools-extensions/foo/panel.js b/spec-main/fixtures/devtools-extensions/foo/panel.js
index d3dad58f3fb8..8b877b389cab 100644
--- a/spec-main/fixtures/devtools-extensions/foo/panel.js
+++ b/spec-main/fixtures/devtools-extensions/foo/panel.js
@@ -54,24 +54,26 @@ testStorage(function (
   syncForRemove, localForRemove,
   syncForClear, localForClear
 ) {
-  const message = JSON.stringify({
-    runtimeId: chrome.runtime.id,
-    tabId: chrome.devtools.inspectedWindow.tabId,
-    i18nString: chrome.i18n.getMessage('foo', ['bar', 'baz']),
-    storageItems: {
-      local: {
-        set: localForSet,
-        remove: localForRemove,
-        clear: localForClear
-      },
-      sync: {
-        set: syncForSet,
-        remove: syncForRemove,
-        clear: syncForClear
+  setTimeout(() => {
+    const message = JSON.stringify({
+      runtimeId: chrome.runtime.id,
+      tabId: chrome.devtools.inspectedWindow.tabId,
+      i18nString: chrome.i18n.getMessage('foo', ['bar', 'baz']),
+      storageItems: {
+        local: {
+          set: localForSet,
+          remove: localForRemove,
+          clear: localForClear
+        },
+        sync: {
+          set: syncForSet,
+          remove: syncForRemove,
+          clear: syncForClear
+        }
       }
-    }
-  });
+    });
 
-  const sendMessage = `require('electron').ipcRenderer.send('answer', ${message})`;
-  window.chrome.devtools.inspectedWindow.eval(sendMessage, function () {});
+    const sendMessage = `require('electron').ipcRenderer.send('answer', ${message})`;
+    window.chrome.devtools.inspectedWindow.eval(sendMessage, function () {});
+  });
 });