From 71b10b6d9785632077ad963f4081cb72d716c26a Mon Sep 17 00:00:00 2001
From: akira <ye.ton@northeastern.edu>
Date: Tue, 11 Aug 2026 10:57:49 -0700
Subject: [PATCH 1/3] feat(workbench): support FDC3 event listeners

---
 CHANGELOG.md                                  |   1 +
 toolbox/fdc3-workbench/package.json           |   1 +
 .../src/components/ChannelField.tsx           |  31 +++
 .../src/components/Channels.tsx               |  40 ++++
 .../src/components/IntentResolutionField.tsx  |   1 +
 .../Workbench/PrivateChannelListeners.tsx     |  28 ++-
 .../src/fixtures/codeExamples.ts              |  34 ++-
 .../src/fixtures/logMessages.ts               |   7 +
 .../src/store/ChannelStore.test.ts            |  82 +++++++
 .../fdc3-workbench/src/store/ChannelStore.ts  |  84 ++++++-
 .../fdc3-workbench/src/store/IntentStore.ts   |   5 +-
 .../src/store/PrivateChannelStore.test.ts     | 133 +++++++++++
 .../src/store/PrivateChannelStore.tsx         | 225 ++++++++++++------
 .../src/store/SystemLogStore.ts               |   4 +-
 14 files changed, 582 insertions(+), 94 deletions(-)
 create mode 100644 toolbox/fdc3-workbench/src/store/ChannelStore.test.ts
 create mode 100644 toolbox/fdc3-workbench/src/store/PrivateChannelStore.test.ts

diff --git a/CHANGELOG.md b/CHANGELOG.md
index b658219c4c..b9836018b5 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 ### Added
 
+* Added FDC3 Workbench support for `DesktopAgent` and `PrivateChannel` events, including automatic user channel updates, private channel event reporting, context-type-aware streaming, FDC3 2.0-2.1 compatibility, and copyable code examples. ([#1674](https://github.com/finos/FDC3/issues/1674))
 * Added conformance coverage for `ChannelError.NoChannelFound`, `ChannelError.MalformedContext`, and `ChannelError.InvalidArguments`. ([#1779](https://github.com/finos/FDC3/issues/1779))
 * Added conformance coverage verifying that Desktop Agent methods continue to work when destructured from the `fdc3` object. ([#1778](https://github.com/finos/FDC3/issues/1778))
 * Added standalone Workbench examples for the FDC3 2.2 `fdc3.action`, `fdc3.fileAttachment`, `fdc3.message`, `fdc3.orderList`, `fdc3.tradeList`, and `fdc3.timeRange` context types. ([#1949](https://github.com/finos/FDC3/pull/1949))
diff --git a/toolbox/fdc3-workbench/package.json b/toolbox/fdc3-workbench/package.json
index 199522df63..0d93a852f8 100644
--- a/toolbox/fdc3-workbench/package.json
+++ b/toolbox/fdc3-workbench/package.json
@@ -13,6 +13,7 @@
     "start": "vite",
     "preview": "vite preview",
     "build": "tsc && vite build",
+    "test": "vitest run",
     "lint": " eslint src/",
     "lint:fix": "eslint --fix src/**/*.{ts,tsx} && prettier --write src/**/*.{ts,tsx}"
   },
diff --git a/toolbox/fdc3-workbench/src/components/ChannelField.tsx b/toolbox/fdc3-workbench/src/components/ChannelField.tsx
index 1a17f34a11..6709fc57aa 100644
--- a/toolbox/fdc3-workbench/src/components/ChannelField.tsx
+++ b/toolbox/fdc3-workbench/src/components/ChannelField.tsx
@@ -341,6 +341,37 @@ export const ChannelField = observer(
                     </Link>
                   </Grid>
                 </Grid>
+                {isPrivateChannel && (
+                  <Grid container sx={styles.secondMargin} alignItems="center">
+                    <Grid item sx={styles.field}>
+                      <Typography variant="h6" sx={styles.h6}>
+                        Private channel events
+                      </Typography>
+                      <Typography variant="body2">
+                        Received events are shown in the Workbench listeners panel.
+                      </Typography>
+                    </Grid>
+                    <Grid item container sx={styles.controls} sm={5} justifyContent="flex-end">
+                      <Tooltip title="Copy code example" aria-label="Copy code example">
+                        <IconButton
+                          size="small"
+                          aria-label="Copy code example"
+                          color="primary"
+                          onClick={copyToClipboard(codeExamples.privateChannelEvents, 'privateChannelEvents')}
+                        >
+                          <FileCopyIcon />
+                        </IconButton>
+                      </Tooltip>
+                      <Link
+                        onClick={openApiDocsLink}
+                        target="FDC3APIDocs"
+                        href="https://fdc3.finos.org/docs/api/ref/PrivateChannel#addeventlistener"
+                      >
+                        <InfoOutlinedIcon />
+                      </Link>
+                    </Grid>
+                  </Grid>
+                )}
                 <Button
                   variant="contained"
                   color="secondary"
diff --git a/toolbox/fdc3-workbench/src/components/Channels.tsx b/toolbox/fdc3-workbench/src/components/Channels.tsx
index e6795d578b..0590e2bbfb 100644
--- a/toolbox/fdc3-workbench/src/components/Channels.tsx
+++ b/toolbox/fdc3-workbench/src/components/Channels.tsx
@@ -175,6 +175,46 @@ export const Channels = observer(
 
         <div style={styles.border}></div>
 
+        <Grid item xs={12}>
+          <Typography variant="h5">User channel events</Typography>
+        </Grid>
+        <Grid container direction="row" justifyContent="space-between" sx={styles.controls}>
+          <Grid item sx={styles.dropDown}>
+            <Typography variant="body1">
+              {channelStore.isUserChannelChangedListenerActive
+                ? 'Listening for userChannelChanged events'
+                : 'Event listener unavailable (requires FDC3 2.2+)'}
+            </Typography>
+          </Grid>
+          <Grid item>
+            <Grid container direction="row" justifyContent="flex-end" spacing={1}>
+              <Grid item sx={styles.controls}>
+                <Tooltip title="Copy code example" aria-label="Copy code example">
+                  <IconButton
+                    size="small"
+                    aria-label="Copy code example"
+                    color="primary"
+                    onClick={copyToClipboard(codeExamples.userChannelChangedEvent, 'userChannelChanged')}
+                  >
+                    <FileCopyIcon />
+                  </IconButton>
+                </Tooltip>
+              </Grid>
+              <Grid item sx={styles.controls}>
+                <Link
+                  onClick={openApiDocsLink}
+                  target="FDC3APIDocs"
+                  href="https://fdc3.finos.org/docs/api/ref/DesktopAgent#addeventlistener"
+                >
+                  <InfoOutlinedIcon />
+                </Link>
+              </Grid>
+            </Grid>
+          </Grid>
+        </Grid>
+
+        <div style={styles.border}></div>
+
         <Grid item xs={12}>
           <Typography variant="h5">Join user channels</Typography>
         </Grid>
diff --git a/toolbox/fdc3-workbench/src/components/IntentResolutionField.tsx b/toolbox/fdc3-workbench/src/components/IntentResolutionField.tsx
index 5e0f33547e..29cbdd848b 100644
--- a/toolbox/fdc3-workbench/src/components/IntentResolutionField.tsx
+++ b/toolbox/fdc3-workbench/src/components/IntentResolutionField.tsx
@@ -61,6 +61,7 @@ export const IntentResolutionField = observer(
               setPrivateChannel(true);
               setChannelsList([{ id: channel.id, channel: channel }]);
               privateChannelStore.addChannelListener(channel as PrivateChannel, 'all');
+              await privateChannelStore.listenForEvents(channel as PrivateChannel);
             }
             setResolutionResult(null);
           } else if (result) {
diff --git a/toolbox/fdc3-workbench/src/components/Workbench/PrivateChannelListeners.tsx b/toolbox/fdc3-workbench/src/components/Workbench/PrivateChannelListeners.tsx
index cf97479cf4..28c76ba8fa 100644
--- a/toolbox/fdc3-workbench/src/components/Workbench/PrivateChannelListeners.tsx
+++ b/toolbox/fdc3-workbench/src/components/Workbench/PrivateChannelListeners.tsx
@@ -22,6 +22,7 @@ const classes = {
 
 export const PrivateChannelListeners = observer(() => {
   const contextListeners: AccordionListItem[] = [];
+  const channelEvents: AccordionListItem[] = [];
 
   privateChannelStore.channelListeners.forEach(({ id, channelId, type, lastReceivedContext, metaData }) => {
     const receivedContextListenerValue = lastReceivedContext ? JSON.stringify(lastReceivedContext, undefined, 4) : '';
@@ -51,17 +52,30 @@ export const PrivateChannelListeners = observer(() => {
     contextListeners.push({ id, textPrimary: `Channel Id: ${channelId}: ${type}`, afterEachElement: contextField });
   });
 
+  privateChannelStore.privateChannelEvents.forEach(({ id, channelId, type, contextType }) => {
+    const eventDetails = type === 'disconnect' ? type : `${type}: ${contextType ?? 'all context types'}`;
+    channelEvents.push({ id, textPrimary: `Channel Id: ${channelId}: ${eventDetails}` });
+  });
+
   const handleDeleteListener = (id: string) => {
     privateChannelStore.removeContextListener(id);
   };
 
   return (
-    <AccordionList
-      title="Private Channels"
-      icon="Any context already in the channel will NOT be received automatically"
-      noItemsText="No Private Channel Listeners"
-      listItems={contextListeners}
-      onDelete={handleDeleteListener}
-    />
+    <>
+      <AccordionList
+        title="Private Channels"
+        icon="Any context already in the channel will NOT be received automatically"
+        noItemsText="No Private Channel Listeners"
+        listItems={contextListeners}
+        onDelete={handleDeleteListener}
+      />
+      <AccordionList
+        title="Private Channel Events"
+        icon="Shows context listener and disconnect events received from private channels"
+        noItemsText="No Private Channel Events"
+        listItems={channelEvents}
+      />
+    </>
   );
 });
diff --git a/toolbox/fdc3-workbench/src/fixtures/codeExamples.ts b/toolbox/fdc3-workbench/src/fixtures/codeExamples.ts
index d8317dca5c..05bc1f9e58 100644
--- a/toolbox/fdc3-workbench/src/fixtures/codeExamples.ts
+++ b/toolbox/fdc3-workbench/src/fixtures/codeExamples.ts
@@ -17,6 +17,14 @@ let current = await fdc3.getCurrentChannel();
 //leave the current channel\nawait fdc3.leaveCurrentChannel();
 //the fdc3Listener will now cease receiving context`,
 
+  userChannelChangedEvent: `// FDC3 2.2+
+const listener = await fdc3.addEventListener('userChannelChanged', event => {
+    console.log('Current user channel:', event.details.currentChannelId);
+});
+
+// Stop listening when the event is no longer needed
+await listener.unsubscribe();`,
+
   broadcast: `const instrument = {
     type: 'fdc3.instrument',
     id: {
@@ -78,6 +86,19 @@ const contactListener = appChannel.addContextListener('fdc3.contact', contact =>
     //add context handling code here
 });`,
 
+  privateChannelEvents: `// FDC3 2.2+
+const added = await privateChannel.addEventListener('addContextListener', event => {
+    console.log('Listener added for:', event.details.contextType ?? 'all');
+});
+
+const removed = await privateChannel.addEventListener('unsubscribe', event => {
+    console.log('Listener removed for:', event.details.contextType ?? 'all');
+});
+
+const disconnected = await privateChannel.addEventListener('disconnect', () => {
+    console.log('The other participant disconnected');
+});`,
+
   intentListener: `const listener = fdc3.addIntentListener('StartChat', context => {
   // start chat has been requested by another application
 });`,
@@ -100,9 +121,20 @@ const listener = fdc3.addIntentListener('StartChat', context => {
 	return channel;
 });`,
 
-  intentListenerWithPrivateChannel: `const listener = fdc3.addIntentListener('StartChat', context => {
+  intentListenerWithPrivateChannel: `const listener = fdc3.addIntentListener('StartChat', async context => {
 	// start chat has been requested by another application
 	const channel = await fdc3.createPrivateChannel();
+
+	await channel.addEventListener('addContextListener', event => {
+		console.log('Listener added for:', event.details.contextType ?? 'all');
+	});
+	await channel.addEventListener('unsubscribe', event => {
+		console.log('Listener removed for:', event.details.contextType ?? 'all');
+	});
+	await channel.addEventListener('disconnect', () => {
+		console.log('The other participant disconnected');
+	});
+
 	return channel;
 });`,
 
diff --git a/toolbox/fdc3-workbench/src/fixtures/logMessages.ts b/toolbox/fdc3-workbench/src/fixtures/logMessages.ts
index 5cf2ee85b0..b9df8b6718 100644
--- a/toolbox/fdc3-workbench/src/fixtures/logMessages.ts
+++ b/toolbox/fdc3-workbench/src/fixtures/logMessages.ts
@@ -19,6 +19,10 @@ export const getLogMessage = (name: logMessagesName, type: logMessagesType, valu
       success: `Retrieved current channel [${value}]`,
       error: `Failed to retrieve current channel`,
     },
+    userChannelChanged: {
+      info: `User channel changed to [${value}]`,
+      error: `Failed to listen for user channel changes`,
+    },
     joinUserChannel: {
       success: `Joined the [${value}] channel`,
       error: `Failed to join the [${value}] channel`,
@@ -112,6 +116,9 @@ export const getLogMessage = (name: logMessagesName, type: logMessagesType, valu
       success: `${value}`,
       error: `${value}`,
     },
+    privateChannelEventListener: {
+      error: `Failed to listen for events on private channel [${value}]`,
+    },
   };
 
   return logMessages[name][type] ?? (value != '' ? `${value}` : `Undefined log message ${name}.${type}`);
diff --git a/toolbox/fdc3-workbench/src/store/ChannelStore.test.ts b/toolbox/fdc3-workbench/src/store/ChannelStore.test.ts
new file mode 100644
index 0000000000..0129835ea5
--- /dev/null
+++ b/toolbox/fdc3-workbench/src/store/ChannelStore.test.ts
@@ -0,0 +1,82 @@
+/**
+ * SPDX-License-Identifier: Apache-2.0
+ * Copyright FINOS FDC3 contributors - see NOTICE file
+ */
+import { Channel, DesktopAgent, EventHandler, Listener } from '@finos/fdc3';
+import { afterEach, describe, expect, it, vi } from 'vitest';
+import systemLogStore from './SystemLogStore.js';
+import { ChannelStore } from './ChannelStore.js';
+
+const createListener = (): Listener => ({
+  unsubscribe: vi.fn(),
+});
+
+describe('ChannelStore event support', () => {
+  afterEach(() => {
+    systemLogStore.logList = [];
+  });
+
+  it('updates the current user channel when a 2.2 event is received', async () => {
+    const channels = [{ id: 'red' }, { id: 'green' }] as Channel[];
+    let eventHandler: EventHandler | undefined;
+    const agent = {
+      getUserChannels: vi.fn().mockResolvedValue(channels),
+      getCurrentChannel: vi.fn().mockResolvedValue(channels[0]),
+      getInfo: vi.fn().mockResolvedValue({ fdc3Version: '2.2' }),
+      addEventListener: vi.fn(async (_type: string, handler: EventHandler) => {
+        eventHandler = handler;
+        return createListener();
+      }),
+    } as unknown as DesktopAgent;
+    const store = new ChannelStore(async () => agent, false);
+
+    await store.getUserChannels();
+    await store.listenForUserChannelChanges();
+    eventHandler?.({
+      type: 'userChannelChanged',
+      details: { currentChannelId: 'green' },
+    });
+
+    expect(agent.addEventListener).toHaveBeenCalledWith('userChannelChanged', expect.any(Function));
+    expect(store.isUserChannelChangedListenerActive).toBe(true);
+    expect(store.currentUserChannel).toEqual(channels[1]);
+    expect(systemLogStore.logList.at(-1)?.message).toBe('User channel changed to [green]');
+  });
+
+  it('clears the current user channel when the event reports no channel', async () => {
+    const channel = { id: 'red' } as Channel;
+    let eventHandler: EventHandler | undefined;
+    const agent = {
+      getUserChannels: vi.fn().mockResolvedValue([channel]),
+      getCurrentChannel: vi.fn().mockResolvedValue(channel),
+      getInfo: vi.fn().mockResolvedValue({ fdc3Version: '3.0.0' }),
+      addEventListener: vi.fn(async (_type: string, handler: EventHandler) => {
+        eventHandler = handler;
+        return createListener();
+      }),
+    } as unknown as DesktopAgent;
+    const store = new ChannelStore(async () => agent, false);
+
+    await store.getUserChannels();
+    await store.listenForUserChannelChanges();
+    eventHandler?.({
+      type: 'userChannelChanged',
+      details: { currentChannelId: null },
+    });
+
+    expect(store.currentUserChannel).toBeNull();
+  });
+
+  it('does not register the new event API for FDC3 2.1', async () => {
+    const agent = {
+      getInfo: vi.fn().mockResolvedValue({ fdc3Version: '2.1' }),
+      addEventListener: vi.fn(),
+    } as unknown as DesktopAgent;
+    const store = new ChannelStore(async () => agent, false);
+
+    await store.listenForUserChannelChanges();
+
+    expect(agent.addEventListener).not.toHaveBeenCalled();
+    expect(store.isUserChannelChangedListenerActive).toBe(false);
+  });
+});
diff --git a/toolbox/fdc3-workbench/src/store/ChannelStore.ts b/toolbox/fdc3-workbench/src/store/ChannelStore.ts
index 8e3104f5d3..2d47064d5f 100644
--- a/toolbox/fdc3-workbench/src/store/ChannelStore.ts
+++ b/toolbox/fdc3-workbench/src/store/ChannelStore.ts
@@ -2,31 +2,49 @@
  * SPDX-License-Identifier: Apache-2.0
  * Copyright FINOS FDC3 contributors - see NOTICE file
  */
-import { makeObservable, observable, action, runInAction } from 'mobx';
+import { action, makeObservable, observable, runInAction } from 'mobx';
 import systemLogStore from './SystemLogStore.js';
-import { Channel } from '@finos/fdc3';
+import { Channel, DesktopAgent, FDC3ChannelChangedEvent, Listener, versionIsAtLeast } from '@finos/fdc3';
 import { getWorkbenchAgent } from '../utility/Fdc3Api.js';
 
-class ChannelStore {
+type WorkbenchAgentProvider = () => Promise<DesktopAgent>;
+
+export class ChannelStore {
   userChannels: Channel[] = [];
 
   currentUserChannel: Channel | null = null;
 
-  constructor() {
+  isUserChannelChangedListenerActive = false;
+
+  private userChannelChangedListener: Listener | null = null;
+
+  constructor(
+    private readonly getAgent: WorkbenchAgentProvider = getWorkbenchAgent,
+    autoInitialize = typeof window !== 'undefined'
+  ) {
     makeObservable(this, {
       userChannels: observable,
       currentUserChannel: observable,
+      isUserChannelChangedListenerActive: observable,
       getUserChannels: action,
       joinUserChannel: action,
       leaveUserChannel: action,
       getCurrentUserChannel: action,
+      listenForUserChannelChanges: action,
     });
 
-    this.getUserChannels();
+    if (autoInitialize) {
+      void this.initialize();
+    }
+  }
+
+  private async initialize() {
+    await this.getUserChannels();
+    await this.listenForUserChannelChanges();
   }
 
   async getCurrentUserChannel() {
-    const agent = await getWorkbenchAgent();
+    const agent = await this.getAgent();
     try {
       const userChannel = await agent.getCurrentChannel();
       runInAction(() => {
@@ -51,7 +69,7 @@ class ChannelStore {
   }
 
   async getUserChannels() {
-    const agent = await getWorkbenchAgent();
+    const agent = await this.getAgent();
     //defer retrieving channels until fdc3 API is ready
     try {
       const userChannels: Channel[] = await agent.getUserChannels();
@@ -77,7 +95,7 @@ class ChannelStore {
   }
 
   async joinUserChannel(channelId: string) {
-    const agent = await getWorkbenchAgent();
+    const agent = await this.getAgent();
     try {
       await agent.joinUserChannel(channelId);
 
@@ -105,7 +123,7 @@ class ChannelStore {
   }
 
   async leaveUserChannel() {
-    const agent = await getWorkbenchAgent();
+    const agent = await this.getAgent();
     try {
       //check that we're on a channel
       let currentUserChannel = await agent.getCurrentChannel();
@@ -144,6 +162,54 @@ class ChannelStore {
       });
     }
   }
+
+  async listenForUserChannelChanges() {
+    if (this.userChannelChangedListener) {
+      return;
+    }
+
+    const agent = await this.getAgent();
+
+    try {
+      const implementationMetadata = await agent.getInfo();
+      if (versionIsAtLeast(implementationMetadata, '2.2') !== true) {
+        return;
+      }
+
+      const listener = await agent.addEventListener('userChannelChanged', event => {
+        const channelId = (event as FDC3ChannelChangedEvent).details.currentChannelId;
+        const currentUserChannel =
+          channelId === null ? null : (this.userChannels.find(channel => channel.id === channelId) ?? null);
+
+        runInAction(() => {
+          this.currentUserChannel = currentUserChannel;
+          systemLogStore.addLog({
+            name: 'userChannelChanged',
+            type: 'info',
+            value: channelId ?? 'none',
+            variant: 'code',
+            body: JSON.stringify(event, null, 4),
+          });
+        });
+
+        if (channelId !== null && currentUserChannel === null) {
+          void this.getCurrentUserChannel();
+        }
+      });
+
+      runInAction(() => {
+        this.userChannelChangedListener = listener;
+        this.isUserChannelChangedListenerActive = true;
+      });
+    } catch (e) {
+      systemLogStore.addLog({
+        name: 'userChannelChanged',
+        type: 'error',
+        variant: 'code',
+        body: JSON.stringify(e, null, 4),
+      });
+    }
+  }
 }
 
 const channelStore = new ChannelStore();
diff --git a/toolbox/fdc3-workbench/src/store/IntentStore.ts b/toolbox/fdc3-workbench/src/store/IntentStore.ts
index dd6c7fe624..d3fa2f0548 100644
--- a/toolbox/fdc3-workbench/src/store/IntentStore.ts
+++ b/toolbox/fdc3-workbench/src/store/IntentStore.ts
@@ -64,10 +64,7 @@ class IntentStore {
         if (isPrivate && !channelName) {
           channel = await privateChannelStore.createPrivateChannel();
           privateChannelStore.addChannelListener(<PrivateChannel>channel, 'all');
-
-          privateChannelStore.onDisconnect(<PrivateChannel>channel);
-          privateChannelStore.onUnsubscribe(<PrivateChannel>channel);
-          privateChannelStore.onAddContextListener(<PrivateChannel>channel, channelContexts, channelContextDelay);
+          await privateChannelStore.listenForEvents(<PrivateChannel>channel, channelContexts, channelContextDelay);
         }
 
         if (!isPrivate && channel) {
diff --git a/toolbox/fdc3-workbench/src/store/PrivateChannelStore.test.ts b/toolbox/fdc3-workbench/src/store/PrivateChannelStore.test.ts
new file mode 100644
index 0000000000..3ce7ba19c3
--- /dev/null
+++ b/toolbox/fdc3-workbench/src/store/PrivateChannelStore.test.ts
@@ -0,0 +1,133 @@
+/**
+ * SPDX-License-Identifier: Apache-2.0
+ * Copyright FINOS FDC3 contributors - see NOTICE file
+ */
+import { DesktopAgent, EventHandler, Listener, PrivateChannel } from '@finos/fdc3';
+import { afterEach, describe, expect, it, vi } from 'vitest';
+import systemLogStore from './SystemLogStore.js';
+import { PrivateChannelStore } from './PrivateChannelStore.js';
+
+const createListener = (): Listener => ({
+  unsubscribe: vi.fn(),
+});
+
+interface PrivateChannelHarness {
+  channel: PrivateChannel;
+  eventHandlers: Map<string, EventHandler>;
+  legacyHandlers: {
+    addContextListener?: (contextType?: string) => void;
+    unsubscribe?: (contextType?: string) => void;
+    disconnect?: () => void;
+  };
+  addEventListener: ReturnType<typeof vi.fn>;
+}
+
+const createPrivateChannelHarness = (): PrivateChannelHarness => {
+  const eventHandlers = new Map<string, EventHandler>();
+  const legacyHandlers: PrivateChannelHarness['legacyHandlers'] = {};
+  const addEventListener = vi.fn(async (type: string, handler: EventHandler) => {
+    eventHandlers.set(type, handler);
+    return createListener();
+  });
+  const channel = {
+    id: 'private-1',
+    type: 'private',
+    addEventListener,
+    onAddContextListener: vi.fn((handler: (contextType?: string) => void) => {
+      legacyHandlers.addContextListener = handler;
+      return createListener();
+    }),
+    onUnsubscribe: vi.fn((handler: (contextType?: string) => void) => {
+      legacyHandlers.unsubscribe = handler;
+      return createListener();
+    }),
+    onDisconnect: vi.fn((handler: () => void) => {
+      legacyHandlers.disconnect = handler;
+      return createListener();
+    }),
+    disconnect: vi.fn(),
+  } as unknown as PrivateChannel;
+
+  return { channel, eventHandlers, legacyHandlers, addEventListener };
+};
+
+const createAgentProvider = (fdc3Version: string) => async () =>
+  ({
+    getInfo: vi.fn().mockResolvedValue({ fdc3Version }),
+  }) as unknown as DesktopAgent;
+
+describe('PrivateChannelStore event support', () => {
+  afterEach(() => {
+    vi.useRealTimers();
+    systemLogStore.logList = [];
+  });
+
+  it('uses the 2.2 event API and reports the received context type', async () => {
+    const harness = createPrivateChannelHarness();
+    const store = new PrivateChannelStore(createAgentProvider('2.2'));
+
+    await store.listenForEvents(harness.channel);
+    harness.eventHandlers.get('addContextListener')?.({
+      type: 'addContextListener',
+      details: { contextType: 'fdc3.instrument' },
+    });
+    harness.eventHandlers.get('unsubscribe')?.({
+      type: 'unsubscribe',
+      details: { contextType: 'fdc3.instrument' },
+    });
+
+    expect(harness.addEventListener.mock.calls.map(call => call[0])).toEqual([
+      'addContextListener',
+      'unsubscribe',
+      'disconnect',
+    ]);
+    expect(store.privateChannelEvents.map(event => [event.type, event.contextType])).toEqual([
+      ['addContextListener', 'fdc3.instrument'],
+      ['unsubscribe', 'fdc3.instrument'],
+    ]);
+  });
+
+  it('broadcasts only contexts matching the listener type', async () => {
+    vi.useFakeTimers();
+    const harness = createPrivateChannelHarness();
+    const store = new PrivateChannelStore(createAgentProvider('3.0.0'));
+    const broadcast = vi.spyOn(store, 'broadcast').mockResolvedValue();
+    const instrument = { type: 'fdc3.instrument', id: { ticker: 'AAPL' } };
+    const contact = { type: 'fdc3.contact', id: { email: 'person@example.com' } };
+
+    await store.listenForEvents(harness.channel, { instrument, contact });
+    harness.eventHandlers.get('addContextListener')?.({
+      type: 'addContextListener',
+      details: { contextType: 'fdc3.instrument' },
+    });
+    await vi.runAllTimersAsync();
+
+    expect(broadcast).toHaveBeenCalledOnce();
+    expect(broadcast).toHaveBeenCalledWith(harness.channel, instrument);
+  });
+
+  it('uses deprecated private channel callbacks for FDC3 2.0 and 2.1', async () => {
+    const harness = createPrivateChannelHarness();
+    const store = new PrivateChannelStore(createAgentProvider('2.1'));
+
+    await store.listenForEvents(harness.channel);
+    harness.legacyHandlers.addContextListener?.('fdc3.contact');
+    harness.legacyHandlers.unsubscribe?.('fdc3.contact');
+
+    expect(harness.addEventListener).not.toHaveBeenCalled();
+    expect(store.privateChannelEvents.map(event => [event.type, event.contextType])).toEqual([
+      ['addContextListener', 'fdc3.contact'],
+      ['unsubscribe', 'fdc3.contact'],
+    ]);
+  });
+
+  it('registers event listeners only once per private channel', async () => {
+    const harness = createPrivateChannelHarness();
+    const store = new PrivateChannelStore(createAgentProvider('2.2'));
+
+    await store.listenForEvents(harness.channel);
+    await store.listenForEvents(harness.channel);
+
+    expect(harness.addEventListener).toHaveBeenCalledTimes(3);
+  });
+});
diff --git a/toolbox/fdc3-workbench/src/store/PrivateChannelStore.tsx b/toolbox/fdc3-workbench/src/store/PrivateChannelStore.tsx
index 85971420b0..17c968f994 100644
--- a/toolbox/fdc3-workbench/src/store/PrivateChannelStore.tsx
+++ b/toolbox/fdc3-workbench/src/store/PrivateChannelStore.tsx
@@ -2,44 +2,61 @@
  * SPDX-License-Identifier: Apache-2.0
  * Copyright FINOS FDC3 contributors - see NOTICE file
  */
-import { makeObservable, observable, action, runInAction, toJS } from 'mobx';
-import { ContextType, Fdc3Listener, PrivateChannel } from '../utility/Fdc3Api.js';
-import systemLogStore from './SystemLogStore.js';
+import {
+  ContextMetadata,
+  DesktopAgent,
+  Listener,
+  PrivateChannelAddContextListenerEvent,
+  PrivateChannelUnsubscribeEvent,
+  versionIsAtLeast,
+} from '@finos/fdc3-standard';
+import { action, makeObservable, observable, runInAction, toJS } from 'mobx';
 import { nanoid } from 'nanoid';
-import { getWorkbenchAgent } from '../utility/Fdc3Api.js';
-import { ContextMetadata } from '@finos/fdc3-standard';
-// interface ListenerOptionType {
-// 	title: string;
-// 	value: string;
-// 	type: string | undefined;
-// }
-
-class PrivateChannelStore {
+import { ContextType, Fdc3Listener, getWorkbenchAgent, PrivateChannel } from '../utility/Fdc3Api.js';
+import systemLogStore from './SystemLogStore.js';
+
+interface LegacyPrivateChannel extends PrivateChannel {
+  onAddContextListener(handler: (contextType?: string) => void): Listener;
+  onUnsubscribe(handler: (contextType?: string) => void): Listener;
+  onDisconnect(handler: () => void): Listener;
+}
+
+export interface PrivateChannelEventRecord {
+  id: string;
+  channelId: string;
+  type: 'addContextListener' | 'unsubscribe' | 'disconnect';
+  contextType: string | null;
+}
+
+type WorkbenchAgentProvider = () => Promise<DesktopAgent>;
+
+export class PrivateChannelStore {
   privateChannelsList: PrivateChannel[] = [];
 
   currentPrivateChannel: PrivateChannel | null = null;
 
   channelListeners: Fdc3Listener[] = [];
 
-  constructor() {
+  privateChannelEvents: PrivateChannelEventRecord[] = [];
+
+  private channelEventListeners = new Map<string, Listener[]>();
+
+  constructor(private readonly getAgent: WorkbenchAgentProvider = getWorkbenchAgent) {
     makeObservable(this, {
       privateChannelsList: observable,
       currentPrivateChannel: observable,
       channelListeners: observable,
+      privateChannelEvents: observable,
       createPrivateChannel: action,
       broadcast: action,
-      onAddContextListener: action,
-      onDisconnect: action,
-      onUnsubscribe: action,
+      listenForEvents: action,
       disconnect: action,
     });
   }
 
   async createPrivateChannel() {
     try {
-      const currentPrivateChannel: PrivateChannel = await getWorkbenchAgent().then(agent =>
-        agent.createPrivateChannel()
-      );
+      const currentPrivateChannel = await this.getAgent().then(agent => agent.createPrivateChannel());
       const isSuccess = currentPrivateChannel !== null;
       if (isSuccess) {
         this.privateChannelsList.push(currentPrivateChannel);
@@ -67,7 +84,7 @@ class PrivateChannelStore {
   }
 
   isContextListenerExists(channelId: string, type: string | undefined) {
-    return !!this.channelListeners?.find(listener => listener.type === type && listener.channelId === channelId);
+    return !!this.channelListeners.find(listener => listener.type === type && listener.channelId === channelId);
   }
 
   isPrivateChannelExists(channelId: string) {
@@ -121,10 +138,10 @@ class PrivateChannelStore {
       const foundListener = this.channelListeners.find(
         currentListener => currentListener.type === newListener && currentListener.channelId === channelId
       );
-      if (!foundListener && currentChannel && newListener !== undefined) {
+      if (!foundListener && newListener !== undefined) {
         const listenerId = nanoid();
         const contactListener = await currentChannel.addContextListener(
-          newListener?.toLowerCase() === 'all' ? null : newListener,
+          newListener.toLowerCase() === 'all' ? null : newListener,
           (context, metaData?: ContextMetadata) => {
             const currentListener = this.channelListeners.find(
               listener => listener.type === newListener && listener.channelId === channelId
@@ -162,7 +179,7 @@ class PrivateChannelStore {
   }
 
   removeContextListener(id: string) {
-    const listenerIndex = this.channelListeners?.findIndex(listener => listener.id === id);
+    const listenerIndex = this.channelListeners.findIndex(listener => listener.id === id);
     const listener = this.channelListeners[listenerIndex];
     if (listenerIndex !== -1) {
       try {
@@ -189,83 +206,147 @@ class PrivateChannelStore {
     }
   }
 
-  onAddContextListener(
+  private recordEvent(channel: PrivateChannel, type: PrivateChannelEventRecord['type'], contextType: string | null) {
+    this.privateChannelEvents.push({
+      id: nanoid(),
+      channelId: channel.id,
+      type,
+      contextType,
+    });
+  }
+
+  private onAddContextListenerEvent(
     channel: PrivateChannel,
+    contextType: string | null,
     channelContexts?: Record<string, ContextType>,
     channelContextDelay?: Record<string, number>
   ) {
-    channel.addEventListener('addContextListener', () => {
-      try {
+    try {
+      const displayedContextType = contextType ?? 'all';
+      runInAction(() => {
+        this.recordEvent(channel, 'addContextListener', contextType);
         systemLogStore.addLog({
           name: 'pcAddContextListener',
           type: 'success',
-          value: `A context listener for '[all]' has been added on channel [${channel.id}]`,
+          value: `A context listener for '[${displayedContextType}]' has been added on channel [${channel.id}]`,
         });
+      });
 
-        if (channelContexts && Object.keys(channelContexts).length !== 0) {
-          Object.keys(channelContexts).forEach(key => {
-            const broadcast = setTimeout(async () => {
-              this.broadcast(channel, channelContexts[key]);
-              clearTimeout(broadcast);
-            }, channelContextDelay?.[key] ?? 0);
-          });
-        }
-      } catch {
-        systemLogStore.addLog({
-          name: 'pcAddContextListener',
-          type: 'error',
-          value: `Failed to add a context listener for '[all]' on channel [${channel.id}]`,
+      Object.entries(channelContexts ?? {})
+        .filter(([, context]) => contextType === null || context.type === contextType)
+        .forEach(([key, context]) => {
+          const broadcast = setTimeout(() => {
+            void this.broadcast(channel, context);
+            clearTimeout(broadcast);
+          }, channelContextDelay?.[key] ?? 0);
         });
-      }
-    });
+    } catch {
+      systemLogStore.addLog({
+        name: 'pcAddContextListener',
+        type: 'error',
+        value: `Failed to handle an added '[${contextType ?? 'all'}]' context listener on channel [${channel.id}]`,
+      });
+    }
   }
 
-  onUnsubscribe(channel: PrivateChannel) {
-    channel.addEventListener('unsubscribe', () => {
-      try {
+  private onUnsubscribeEvent(channel: PrivateChannel, contextType: string | null) {
+    try {
+      runInAction(() => {
+        this.recordEvent(channel, 'unsubscribe', contextType);
         systemLogStore.addLog({
           name: 'pcOnUnsubscribe',
           type: 'success',
-          value: `Sucessfully unsubscribed from listener '[all]' for channel [${channel.id}]`,
-        });
-      } catch {
-        systemLogStore.addLog({
-          name: 'pcOnUnsubscribe',
-          type: 'error',
-          value: `Could not unsubscribed listener '[all]' from channel [${channel.id}]`,
+          value: `Unsubscribed listener '[${contextType ?? 'all'}]' for channel [${channel.id}]`,
         });
-      }
-    });
+      });
+    } catch {
+      systemLogStore.addLog({
+        name: 'pcOnUnsubscribe',
+        type: 'error',
+        value: `Could not process listener '[${contextType ?? 'all'}]' being unsubscribed from channel [${channel.id}]`,
+      });
+    }
   }
 
-  onDisconnect(channel: PrivateChannel) {
-    channel.addEventListener('disconnect', () => {
-      try {
-        this.channelListeners.forEach(listener => {
-          this.removeContextListener(listener.id);
-        });
+  private onDisconnectEvent(channel: PrivateChannel) {
+    try {
+      this.channelListeners
+        .filter(listener => listener.channelId === channel.id)
+        .forEach(listener => this.removeContextListener(listener.id));
+
+      runInAction(() => {
         this.privateChannelsList = this.privateChannelsList.filter(chan => chan.id !== channel.id);
+        this.recordEvent(channel, 'disconnect', null);
         systemLogStore.addLog({
           name: 'pcOnDisconnect',
           type: 'success',
-          value: `Sucessfully disconntected from channel [${channel.id}]`,
-        });
-      } catch {
-        systemLogStore.addLog({
-          name: 'pcOnDisconnect',
-          type: 'error',
-          value: `Unable to disconnect from channel [${channel.id}]`,
+          value: `Disconnected from channel [${channel.id}]`,
         });
+      });
+    } catch {
+      systemLogStore.addLog({
+        name: 'pcOnDisconnect',
+        type: 'error',
+        value: `Unable to disconnect from channel [${channel.id}]`,
+      });
+    }
+  }
+
+  async listenForEvents(
+    channel: PrivateChannel,
+    channelContexts?: Record<string, ContextType>,
+    channelContextDelay?: Record<string, number>
+  ) {
+    if (this.channelEventListeners.has(channel.id)) {
+      return;
+    }
+
+    try {
+      const implementationMetadata = await this.getAgent().then(agent => agent.getInfo());
+      let listeners: Listener[];
+
+      if (versionIsAtLeast(implementationMetadata, '2.2') === true) {
+        listeners = await Promise.all([
+          channel.addEventListener('addContextListener', event => {
+            const contextType = (event as PrivateChannelAddContextListenerEvent).details.contextType;
+            this.onAddContextListenerEvent(channel, contextType, channelContexts, channelContextDelay);
+          }),
+          channel.addEventListener('unsubscribe', event => {
+            const contextType = (event as PrivateChannelUnsubscribeEvent).details.contextType;
+            this.onUnsubscribeEvent(channel, contextType);
+          }),
+          channel.addEventListener('disconnect', () => this.onDisconnectEvent(channel)),
+        ]);
+      } else {
+        const legacyChannel = channel as LegacyPrivateChannel;
+        listeners = [
+          legacyChannel.onAddContextListener(contextType =>
+            this.onAddContextListenerEvent(channel, contextType ?? null, channelContexts, channelContextDelay)
+          ),
+          legacyChannel.onUnsubscribe(contextType => this.onUnsubscribeEvent(channel, contextType ?? null)),
+          legacyChannel.onDisconnect(() => this.onDisconnectEvent(channel)),
+        ];
       }
-    });
+
+      this.channelEventListeners.set(channel.id, listeners);
+    } catch (e) {
+      systemLogStore.addLog({
+        name: 'privateChannelEventListener',
+        type: 'error',
+        value: channel.id,
+        variant: 'code',
+        body: JSON.stringify(e, null, 4),
+      });
+    }
   }
 
   disconnect(channel: PrivateChannel) {
-    this.channelListeners.forEach(listener => {
-      this.removeContextListener(listener.id);
-    });
+    this.channelListeners
+      .filter(listener => listener.channelId === channel.id)
+      .forEach(listener => this.removeContextListener(listener.id));
     this.privateChannelsList = this.privateChannelsList.filter(chan => chan.id !== channel.id);
-    channel.disconnect();
+    this.channelEventListeners.delete(channel.id);
+    void channel.disconnect();
   }
 }
 
diff --git a/toolbox/fdc3-workbench/src/store/SystemLogStore.ts b/toolbox/fdc3-workbench/src/store/SystemLogStore.ts
index 38b5387551..10cd0684ac 100644
--- a/toolbox/fdc3-workbench/src/store/SystemLogStore.ts
+++ b/toolbox/fdc3-workbench/src/store/SystemLogStore.ts
@@ -11,6 +11,7 @@ export type logMessagesName =
   | 'getFdc3'
   | 'getChannels'
   | 'getCurrentChannel'
+  | 'userChannelChanged'
   | 'joinUserChannel'
   | 'leaveChannel'
   | 'broadcast'
@@ -33,7 +34,8 @@ export type logMessagesName =
   | 'removeAppChannelContextListener'
   | 'pcAddContextListener'
   | 'pcOnUnsubscribe'
-  | 'pcOnDisconnect';
+  | 'pcOnDisconnect'
+  | 'privateChannelEventListener';
 
 export type logMessagesType = 'error' | 'success' | 'warning' | 'info';
 

From c2013e4e3ca723df0ce0284dbb9add4a5a061bc1 Mon Sep 17 00:00:00 2001
From: akira <ye.ton@northeastern.edu>
Date: Tue, 11 Aug 2026 23:13:33 -0700
Subject: [PATCH 2/3] fix(workbench): address event listener feedback

---
 CHANGELOG.md                                  |  2 +-
 .../src/components/ChannelField.tsx           |  2 +-
 .../src/store/PrivateChannelStore.test.ts     | 47 +++++++++++++++++--
 .../src/store/PrivateChannelStore.tsx         | 17 +++++--
 4 files changed, 57 insertions(+), 11 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index b9836018b5..6240146a80 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,7 +8,6 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 ### Added
 
-* Added FDC3 Workbench support for `DesktopAgent` and `PrivateChannel` events, including automatic user channel updates, private channel event reporting, context-type-aware streaming, FDC3 2.0-2.1 compatibility, and copyable code examples. ([#1674](https://github.com/finos/FDC3/issues/1674))
 * Added conformance coverage for `ChannelError.NoChannelFound`, `ChannelError.MalformedContext`, and `ChannelError.InvalidArguments`. ([#1779](https://github.com/finos/FDC3/issues/1779))
 * Added conformance coverage verifying that Desktop Agent methods continue to work when destructured from the `fdc3` object. ([#1778](https://github.com/finos/FDC3/issues/1778))
 * Added standalone Workbench examples for the FDC3 2.2 `fdc3.action`, `fdc3.fileAttachment`, `fdc3.message`, `fdc3.orderList`, `fdc3.tradeList`, and `fdc3.timeRange` context types. ([#1949](https://github.com/finos/FDC3/pull/1949))
@@ -34,6 +33,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 * Added labels and tooltips to dropdowns in the FDC3 for Web reference implementation demo. ([#193](https://github.com/finos/FDC3/pull/1932))
 
 * Added `fdc3.close()` API call allowing an app to request that its own window or frame be closed, with `closeRequest`/`closeResponse` DACP messages and `CloseError` enumeration ([#1918](https://github.com/finos/FDC3/pull/1918))
+* Added FDC3 Workbench support for `DesktopAgent` and `PrivateChannel` events, including automatic user channel updates, private channel event reporting, context-type-aware streaming, FDC3 2.0-2.1 compatibility, and copyable code examples. ([#1674](https://github.com/finos/FDC3/issues/1674))
 
 ### Changed
 
diff --git a/toolbox/fdc3-workbench/src/components/ChannelField.tsx b/toolbox/fdc3-workbench/src/components/ChannelField.tsx
index 6709fc57aa..c022f217fd 100644
--- a/toolbox/fdc3-workbench/src/components/ChannelField.tsx
+++ b/toolbox/fdc3-workbench/src/components/ChannelField.tsx
@@ -210,7 +210,7 @@ export const ChannelField = observer(
 
     const handleRemoveOrDisconnect = (channel: Fdc3ChannelRecord) => {
       if (isPrivateChannel) {
-        privateChannelStore.disconnect(channel.channel as PrivateChannel);
+        void privateChannelStore.disconnect(channel.channel as PrivateChannel);
       } else {
         appChannelStore.remove(channel.channel);
       }
diff --git a/toolbox/fdc3-workbench/src/store/PrivateChannelStore.test.ts b/toolbox/fdc3-workbench/src/store/PrivateChannelStore.test.ts
index 3ce7ba19c3..06b5d46d9b 100644
--- a/toolbox/fdc3-workbench/src/store/PrivateChannelStore.test.ts
+++ b/toolbox/fdc3-workbench/src/store/PrivateChannelStore.test.ts
@@ -8,12 +8,13 @@ import systemLogStore from './SystemLogStore.js';
 import { PrivateChannelStore } from './PrivateChannelStore.js';
 
 const createListener = (): Listener => ({
-  unsubscribe: vi.fn(),
+  unsubscribe: vi.fn().mockResolvedValue(undefined),
 });
 
 interface PrivateChannelHarness {
   channel: PrivateChannel;
   eventHandlers: Map<string, EventHandler>;
+  eventListeners: Listener[];
   legacyHandlers: {
     addContextListener?: (contextType?: string) => void;
     unsubscribe?: (contextType?: string) => void;
@@ -24,10 +25,13 @@ interface PrivateChannelHarness {
 
 const createPrivateChannelHarness = (): PrivateChannelHarness => {
   const eventHandlers = new Map<string, EventHandler>();
+  const eventListeners: Listener[] = [];
   const legacyHandlers: PrivateChannelHarness['legacyHandlers'] = {};
   const addEventListener = vi.fn(async (type: string, handler: EventHandler) => {
     eventHandlers.set(type, handler);
-    return createListener();
+    const listener = createListener();
+    eventListeners.push(listener);
+    return listener;
   });
   const channel = {
     id: 'private-1',
@@ -45,10 +49,10 @@ const createPrivateChannelHarness = (): PrivateChannelHarness => {
       legacyHandlers.disconnect = handler;
       return createListener();
     }),
-    disconnect: vi.fn(),
+    disconnect: vi.fn().mockResolvedValue(undefined),
   } as unknown as PrivateChannel;
 
-  return { channel, eventHandlers, legacyHandlers, addEventListener };
+  return { channel, eventHandlers, eventListeners, legacyHandlers, addEventListener };
 };
 
 const createAgentProvider = (fdc3Version: string) => async () =>
@@ -106,6 +110,27 @@ describe('PrivateChannelStore event support', () => {
     expect(broadcast).toHaveBeenCalledWith(harness.channel, instrument);
   });
 
+  it('broadcasts every configured context when an all-listener event omits contextType', async () => {
+    vi.useFakeTimers();
+    const harness = createPrivateChannelHarness();
+    const store = new PrivateChannelStore(createAgentProvider('2.2'));
+    const broadcast = vi.spyOn(store, 'broadcast').mockResolvedValue();
+    const instrument = { type: 'fdc3.instrument', id: { ticker: 'AAPL' } };
+    const contact = { type: 'fdc3.contact', id: { email: 'person@example.com' } };
+
+    await store.listenForEvents(harness.channel, { instrument, contact });
+    harness.eventHandlers.get('addContextListener')?.({
+      type: 'addContextListener',
+      details: {},
+    });
+    await vi.runAllTimersAsync();
+
+    expect(broadcast).toHaveBeenCalledTimes(2);
+    expect(broadcast).toHaveBeenCalledWith(harness.channel, instrument);
+    expect(broadcast).toHaveBeenCalledWith(harness.channel, contact);
+    expect(store.privateChannelEvents.at(-1)?.contextType).toBeNull();
+  });
+
   it('uses deprecated private channel callbacks for FDC3 2.0 and 2.1', async () => {
     const harness = createPrivateChannelHarness();
     const store = new PrivateChannelStore(createAgentProvider('2.1'));
@@ -130,4 +155,18 @@ describe('PrivateChannelStore event support', () => {
 
     expect(harness.addEventListener).toHaveBeenCalledTimes(3);
   });
+
+  it('unsubscribes every event listener when disconnecting', async () => {
+    const harness = createPrivateChannelHarness();
+    const store = new PrivateChannelStore(createAgentProvider('2.2'));
+
+    await store.listenForEvents(harness.channel);
+    await store.disconnect(harness.channel);
+
+    expect(harness.eventListeners).toHaveLength(3);
+    harness.eventListeners.forEach(listener => {
+      expect(listener.unsubscribe).toHaveBeenCalledOnce();
+    });
+    expect(harness.channel.disconnect).toHaveBeenCalledOnce();
+  });
 });
diff --git a/toolbox/fdc3-workbench/src/store/PrivateChannelStore.tsx b/toolbox/fdc3-workbench/src/store/PrivateChannelStore.tsx
index 17c968f994..4a62c51039 100644
--- a/toolbox/fdc3-workbench/src/store/PrivateChannelStore.tsx
+++ b/toolbox/fdc3-workbench/src/store/PrivateChannelStore.tsx
@@ -273,6 +273,7 @@ export class PrivateChannelStore {
       this.channelListeners
         .filter(listener => listener.channelId === channel.id)
         .forEach(listener => this.removeContextListener(listener.id));
+      void this.unsubscribeEventListeners(channel.id);
 
       runInAction(() => {
         this.privateChannelsList = this.privateChannelsList.filter(chan => chan.id !== channel.id);
@@ -308,11 +309,11 @@ export class PrivateChannelStore {
       if (versionIsAtLeast(implementationMetadata, '2.2') === true) {
         listeners = await Promise.all([
           channel.addEventListener('addContextListener', event => {
-            const contextType = (event as PrivateChannelAddContextListenerEvent).details.contextType;
+            const contextType = (event as PrivateChannelAddContextListenerEvent).details.contextType ?? null;
             this.onAddContextListenerEvent(channel, contextType, channelContexts, channelContextDelay);
           }),
           channel.addEventListener('unsubscribe', event => {
-            const contextType = (event as PrivateChannelUnsubscribeEvent).details.contextType;
+            const contextType = (event as PrivateChannelUnsubscribeEvent).details.contextType ?? null;
             this.onUnsubscribeEvent(channel, contextType);
           }),
           channel.addEventListener('disconnect', () => this.onDisconnectEvent(channel)),
@@ -340,13 +341,19 @@ export class PrivateChannelStore {
     }
   }
 
-  disconnect(channel: PrivateChannel) {
+  private async unsubscribeEventListeners(channelId: string) {
+    const listeners = this.channelEventListeners.get(channelId) ?? [];
+    this.channelEventListeners.delete(channelId);
+    await Promise.allSettled(listeners.map(listener => listener.unsubscribe()));
+  }
+
+  async disconnect(channel: PrivateChannel) {
     this.channelListeners
       .filter(listener => listener.channelId === channel.id)
       .forEach(listener => this.removeContextListener(listener.id));
     this.privateChannelsList = this.privateChannelsList.filter(chan => chan.id !== channel.id);
-    this.channelEventListeners.delete(channel.id);
-    void channel.disconnect();
+    await this.unsubscribeEventListeners(channel.id);
+    await channel.disconnect();
   }
 }
 

From 3eb8a1270eaff9f6a6f93ce9fcfba3f867854653 Mon Sep 17 00:00:00 2001
From: akira <ye.ton@northeastern.edu>
Date: Wed, 9 Sep 2026 08:42:05 -0700
Subject: [PATCH 3/3] test(workbench): build local FDC3 package first

---
 toolbox/fdc3-workbench/package.json | 1 +
 1 file changed, 1 insertion(+)

diff --git a/toolbox/fdc3-workbench/package.json b/toolbox/fdc3-workbench/package.json
index 03e39a4ac2..f7e460036e 100644
--- a/toolbox/fdc3-workbench/package.json
+++ b/toolbox/fdc3-workbench/package.json
@@ -13,6 +13,7 @@
     "start": "vite",
     "preview": "vite preview",
     "build": "tsc && vite build",
+    "pretest": "npm run build --workspace=@finos/fdc3",
     "test": "vitest run",
     "lint": " eslint src/",
     "lint:fix": "eslint --fix src/**/*.{ts,tsx} && prettier --write src/**/*.{ts,tsx}"