diff --git a/package.json b/package.json
index 106488e..ab0f5bc 100644
--- a/package.json
+++ b/package.json
@@ -2,7 +2,7 @@
   "name": "testpilot-containers",
   "title": "Containers Experiment",
   "description": "Containers works by isolating cookie jars using separate origin-attributes defined visually by colored ‘Container Tabs’. This add-on is a modified version of the containers feature for Firefox Test Pilot.",
-  "version": "2.1.1",
+  "version": "2.1.2",
   "author": "Andrea Marchesini, Luke Crouch and Jonathan Kingston",
   "bugs": {
     "url": "https://github.com/mozilla/testpilot-containers/issues"
diff --git a/webextension/background.js b/webextension/background.js
index 57e7c6a..4fd82a5 100644
--- a/webextension/background.js
+++ b/webextension/background.js
@@ -125,7 +125,7 @@ const assignManager = {
           return {};
         }
 
-        this.reloadPageInContainer(options.url, siteSettings.userContextId, tab.index, siteSettings.neverAsk);
+        this.reloadPageInContainer(options.url, siteSettings.userContextId, tab.index + 1, siteSettings.neverAsk);
         this.calculateContextMenu(tab);
         // If the user just opened the tab, we can auto close it
         if (this.CLOSEABLE_WINDOWS.has(tab.url)) {
diff --git a/webextension/manifest.json b/webextension/manifest.json
index a3f4c61..4e30c9d 100644
--- a/webextension/manifest.json
+++ b/webextension/manifest.json
@@ -1,7 +1,7 @@
 {
   "manifest_version": 2,
   "name": "Containers Experiment",
-  "version": "2.1.1",
+  "version": "2.1.2",
 
   "description": "Containers works by isolating cookie jars using separate origin-attributes defined visually by colored ‘Container Tabs’. This add-on is a modified version of the containers feature for Firefox Test Pilot.",
   "icons": {