diff --git a/src/components/MessagePanel/message-panel.jsx b/src/components/MessagePanel/message-panel.jsx
index 2df78df..4fc40fb 100644
--- a/src/components/MessagePanel/message-panel.jsx
+++ b/src/components/MessagePanel/message-panel.jsx
@@ -52,13 +52,14 @@ class MessagePanel extends Component {
   replyMessage(event) {
     let payloadStructure;
 
-    if (event.data.messageType.includes('scratchpad.')) {
+    const messageTarget = event.data.messageType.split('.');
+    if (messageTarget[0] === 'scratchpad') {
       payloadStructure = {
         status: 200,
         location: 'https://resource-location/',
         outcome: 'Success',
       };
-    } else if (event.data.messageType.includes('ui.')) {
+    } else if (messageTarget[0] === 'ui') {
       payloadStructure = {
         success: true,
         details: 'Success',
@@ -74,32 +75,37 @@ class MessagePanel extends Component {
     event.source.postMessage(msgStructure, event.origin);
   }
 
-  addMessage(event) {
-    if (event.origin.includes(document.domain)) {
-      console.log(`Received message from ${event.origin} but it is the same as the current document's domain: ${document.domain}.`);
-      return;
-    }
-
-    console.log(`Received message from ${event.origin}.`);
+  isActionableMessage(event) {
+    // Ignore the event, if it doesn't meet our expectations.
+    if (!event.data) return false;
+    if ((event.data.source || "").startsWith('react-devtools-')) return false;
 
     if (!event.data.messageId) {
-      console.log('Message did not have a messageId and will be ignored.');
-      return;
+      console.warn('Message has no messageId.');
+      return false;
     }
 
     if (!event.data.messageType) {
-      console.log('Message did not have a messageType and will be ignored.');
-      return;
+      console.warn('Message has no messageType.');
+      return false;
     }
 
-    if (!(event.data.messageType.includes('scratchpad.') || event.data.messageType.includes('ui.'))) {
-      console.log('Message did not have a supported messageType and will be ignored.');
-      return;
+    const messageTarget = event.data.messageType.split('.');
+    if (!['scratchpad', 'ui'].includes(messageTarget[0])) {
+      console.warn(`Unknown message type '${messageTarget[0]}.`);
+      return false;
     }
 
-    const message = JSON.stringify(event.data, null, 2);
-    this.setState({ messages: [...this.state.messages, message] });
-    this.replyMessage(event);
+    return true;
+  }
+
+  addMessage(event) {
+    if (this.isActionableMessage(event)) {
+      const message = JSON.stringify(event.data, null, 2);
+      // TODO(issue#129): convert this to a stack so newer messages are on top.
+      this.setState({ messages: [...this.state.messages, message] });
+      this.replyMessage(event);
+    }
   }
 
   /**
diff --git a/src/middleware/cds-execution.js b/src/middleware/cds-execution.js
index 4bbf4f9..d9ea17f 100644
--- a/src/middleware/cds-execution.js
+++ b/src/middleware/cds-execution.js
@@ -151,7 +151,7 @@ const onSystemActions = (action, next, pre, post) => {
 const webMessageMiddleware = (store) => (next) => {
   window.addEventListener('message', ({ data, origin, source }) => {
     Object.entries(windowsRegistered)
-      .filter(([windowId, w]) => w.sourceWindow === source)
+      .filter(([windowId, w]) => w.sourceWindow === source && w.origin === origin)
       .map(([windowId, w]) => w.triggerPoint)
       .map((triggerPoint) => triggerHandlers[triggerPoint])
       .forEach((handler) => handler.onMessage({
diff --git a/src/reducers/hook-reducers.js b/src/reducers/hook-reducers.js
index 75a0ac6..5800425 100644
--- a/src/reducers/hook-reducers.js
+++ b/src/reducers/hook-reducers.js
@@ -49,9 +49,10 @@ const hookReducers = (state = initialState, action) => {
         return { ...state, isLoadingData: action.isLoaderOn };
       }
       case types.LAUNCH_SMART_APP: {
+        const url = new URL(action.link.url);
         const { windowId } = cdsExecution.registerWindow(
           action.triggerPoint,
-          action.link,
+          url.origin,
           action.sourceWindow,
         );
         return {
@@ -61,6 +62,7 @@ const hookReducers = (state = initialState, action) => {
             {
               triggerPoint: action.triggerPoint,
               link: action.link,
+              linkOrigin: url.origin,
               windowId,
             },
           ],
diff --git a/tests/middleware/cds-execution.test.js b/tests/middleware/cds-execution.test.js
index 9b11188..d8c45f4 100644
--- a/tests/middleware/cds-execution.test.js
+++ b/tests/middleware/cds-execution.test.js
@@ -45,7 +45,7 @@ describe("CDS Execution Middleware", () => {
       unregister: unregisterWindow
     } = cdsExecution.registerWindow(
       "example-trigger-point",
-      "fake-origin",
+      "",  // jsdom makes the origin look empty
       null // jsdom makes the source window look `null`
     );
 
diff --git a/tests/reducers/hook-reducers.test.js b/tests/reducers/hook-reducers.test.js
index d07dd99..bf1c573 100644
--- a/tests/reducers/hook-reducers.test.js
+++ b/tests/reducers/hook-reducers.test.js
@@ -6,6 +6,7 @@ describe('Hook Reducer', () => {
 
   beforeEach(() => {
     state = {
+      apps: [],
       currentHook: 'patient-view',
       isLoadingData: false,
       isContextVisible: true,
@@ -28,6 +29,28 @@ describe('Hook Reducer', () => {
     });
   });
 
+  describe('LAUNCH_SMART_APP', () => {
+    it('should extract the origin from a link url', () => {
+      const action = {
+        type: types.LAUNCH_SMART_APP,
+        triggerPoint: 'patient-view',
+        link: {
+          url: 'http://localhost:8080/foo/bar/ignored',
+        },
+        sourceWindow: 'abcdefgh-ijkl-mnop-qrst-uvwxyz012345',
+      };
+      const expectedApp = {
+        triggerPoint: action.triggerPoint,
+        link: action.link,
+        linkOrigin: 'http://localhost:8080',
+        windowId: 0,
+      };
+      const expected = Object.assign({}, state, { apps: [ expectedApp ] });
+      const actual = reducer(state, action);
+      expect(actual).toEqual(expected);
+    })
+  });
+
   describe('SET_CONTEXT_VISIBILITY', () => {
     it('should handle the SET_CONTEXT_VISIBILITY action accordingly', () => {
       const action = {