--- a/devtools/client/application/initializer.js
+++ b/devtools/client/application/initializer.js
@@ -22,16 +22,17 @@ const App = createFactory(require("./src
 
 /**
  * Global Application object in this panel. This object is expected by panel.js and is
  * called to start the UI for the panel.
  */
 window.Application = {
   async bootstrap({ toolbox, panel }) {
     this.updateWorkers = this.updateWorkers.bind(this);
+    this.updateDomain = this.updateDomain.bind(this);
 
     this.mount = document.querySelector("#mount");
     this.toolbox = toolbox;
     this.client = toolbox.target.client;
 
     this.store = configureStore();
     this.actions = bindActionCreators(actions, this.store.dispatch);
 
@@ -54,30 +55,38 @@ window.Application = {
     // Render the root Application component.
     const app = App({ client: this.client, serviceContainer });
     render(Provider({ store: this.store }, app), this.mount);
 
     this.client.addListener("workerListChanged", this.updateWorkers);
     this.client.addListener("serviceWorkerRegistrationListChanged", this.updateWorkers);
     this.client.addListener("registration-changed", this.updateWorkers);
     this.client.addListener("processListChanged", this.updateWorkers);
+    this.toolbox.target.on("navigate", this.updateDomain);
 
+    this.updateDomain();
     await this.updateWorkers();
   },
 
   async updateWorkers() {
     let { service } = await this.client.mainRoot.listAllWorkers();
     this.actions.updateWorkers(service);
   },
 
+  updateDomain() {
+    this.actions.updateDomain(this.toolbox.target.url);
+  },
+
   destroy() {
     this.client.removeListener("workerListChanged", this.updateWorkers);
     this.client.removeListener("serviceWorkerRegistrationListChanged",
       this.updateWorkers);
     this.client.removeListener("registration-changed", this.updateWorkers);
     this.client.removeListener("processListChanged", this.updateWorkers);
 
+    this.toolbox.target.off("navigate", this.updateDomain);
+
     unmountComponentAtNode(this.mount);
     this.mount = null;
     this.toolbox = null;
     this.client = null;
   },
 };

--- a/devtools/client/application/src/actions/index.js
+++ b/devtools/client/application/src/actions/index.js
@@ -1,11 +1,13 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 "use strict";
 
 const workers = require("./workers");
+const page = require("./page");
 
 Object.assign(exports,
   workers,
+  page
 );

--- a/devtools/client/application/src/actions/moz.build
+++ b/devtools/client/application/src/actions/moz.build
@@ -1,8 +1,9 @@
 # This Source Code Form is subject to the terms of the Mozilla Public
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
 DevToolsModules(
     'index.js',
+    'page.js',
     'workers.js',
 )

new file mode 100644
--- /dev/null
+++ b/devtools/client/application/src/actions/page.js
@@ -0,0 +1,20 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+const {
+  UPDATE_DOMAIN,
+} = require("../constants");
+
+function updateDomain(url) {
+  return {
+    type: UPDATE_DOMAIN,
+    url
+  };
+}
+
+module.exports = {
+  updateDomain,
+};

--- a/devtools/client/application/src/components/App.js
+++ b/devtools/client/application/src/components/App.js
@@ -16,31 +16,35 @@ const WorkerListEmpty = createFactory(re
  * This is the main component for the application panel.
  */
 class App extends Component {
   static get propTypes() {
     return {
       client: PropTypes.object.isRequired,
       workers: PropTypes.object.isRequired,
       serviceContainer: PropTypes.object.isRequired,
+      domain: PropTypes.string.isRequired,
     };
   }
 
   render() {
-    let { workers, client, serviceContainer } = this.props;
-    const isEmpty = workers.length == 0;
+    let { workers, domain, client, serviceContainer } = this.props;
+
+    // Filter out workers from other domains
+    workers = workers.filter((x) => new URL(x.url).hostname === domain);
+    const isEmpty = workers.length === 0;
 
     return (
       div(
         { className: `application ${isEmpty ? "empty" : ""}` },
         isEmpty
           ? WorkerListEmpty({ serviceContainer })
           : WorkerList({ workers, client, serviceContainer })
       )
     );
   }
 }
 
 // Exports
 
 module.exports = connect(
-  (state) => ({ workers: state.workers.list }),
+  (state) => ({ workers: state.workers.list, domain: state.page.domain }),
 )(App);

--- a/devtools/client/application/src/constants.js
+++ b/devtools/client/application/src/constants.js
@@ -1,12 +1,13 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 "use strict";
 
 const actionTypes = {
   UPDATE_WORKERS: "UPDATE_WORKERS",
+  UPDATE_DOMAIN: "UPDATE_DOMAIN",
 };
 
 // flatten constants
 module.exports = Object.assign({}, actionTypes);

--- a/devtools/client/application/src/create-store.js
+++ b/devtools/client/application/src/create-store.js
@@ -4,19 +4,21 @@
 
 "use strict";
 
 const { createStore } = require("devtools/client/shared/vendor/redux");
 
 // Reducers
 const rootReducer = require("./reducers/index");
 const { WorkersState } = require("./reducers/workers-state");
+const { PageState } = require("./reducers/page-state");
 
 function configureStore() {
   // Prepare initial state.
   const initialState = {
     workers: new WorkersState(),
+    page: new PageState(),
   };
 
   return createStore(rootReducer, initialState);
 }
 
 exports.configureStore = configureStore;

--- a/devtools/client/application/src/reducers/index.js
+++ b/devtools/client/application/src/reducers/index.js
@@ -1,12 +1,14 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 "use strict";
 
 const { combineReducers } = require("devtools/client/shared/vendor/redux");
 const { workersReducer } = require("./workers-state");
+const { pageReducer } = require("./page-state");
 
 module.exports = combineReducers({
   workers: workersReducer,
+  page: pageReducer,
 });

--- a/devtools/client/application/src/reducers/moz.build
+++ b/devtools/client/application/src/reducers/moz.build
@@ -1,8 +1,9 @@
 # This Source Code Form is subject to the terms of the Mozilla Public
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
 DevToolsModules(
     'index.js',
+    'page-state.js',
     'workers-state.js',
 )

new file mode 100644
--- /dev/null
+++ b/devtools/client/application/src/reducers/page-state.js
@@ -0,0 +1,39 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+const {
+  UPDATE_DOMAIN,
+} = require("../constants");
+
+function PageState() {
+  return {
+    // Domain
+    domain: null
+  };
+}
+
+function getDomainFromUrl(url) {
+  return new URL(url).hostname;
+}
+
+function pageReducer(state = PageState(), action) {
+  switch (action.type) {
+    case UPDATE_DOMAIN: {
+      let { url } = action;
+      return {
+        domain: getDomainFromUrl(url)
+      };
+    }
+
+    default:
+      return state;
+  }
+}
+
+module.exports = {
+  PageState,
+  pageReducer,
+};