Implement a pinnable task pane in Outlook

The task pane UX shape for add-in commands opens a vertical task pane to the right of an open message or meeting request. This allows an add-in to provide UI for more detailed interactions, such as filling in multiple text fields. This task pane can be shown in the Reading Pane when viewing a list of messages, allowing for quick processing of a message.

However, by default, if a user has an add-in task pane open for a message in the Reading Pane, and then selects a new message, the task pane is automatically closed. For a heavily-used add-in, the user may prefer to keep that pane open, eliminating the need to reactivate the add-in on each message. With pinnable task panes, your add-in can give the user that option.


Although the pinnable task pane feature was introduced in requirement set 1.5, it's currently only available to Microsoft 365 subscribers using the following:

  • Modern Outlook on the web
  • New Outlook on Windows (preview)
  • Classic Outlook 2016 or later on Windows (Build 7668.2000 or later for users in the Current or Microsoft 365 Insider Channels, Build 7900.xxxx or later for users in Deferred channels)
  • Outlook on Mac (Version 16.13.503 or later)


Pinnable task panes aren't available for the following:

  • Appointments/Meetings

Support task pane pinning

The first step is to add pinning support, which is done in the add-in manifest. The markup varies depending on the type of manifest your add-in uses.

Add a "pinnable" property, set to true, to the object in the "actions" array that defines the button or menu item that opens the task pane. The following is an example.

"actions": [
        "id": "OpenTaskPane",
        "type": "openPage",
        "view": "TaskPaneView",
        "displayName": "OpenTaskPane",
        "pinnable": true

For a full example, see the msgReadOpenPaneButton control in the command-demo sample manifest.


Task pane pinning is automatically supported in an add-in that activates without the Reading Pane enabled or a message first selected. To learn more, see Activate your Outlook add-in without the Reading Pane enabled or a message selected.

Handling UI updates based on currently selected message

To update your task pane's UI or internal variables based on the current item, you'll need to register an event handler to get notified of the change.

Implement the event handler

The event handler should accept a single parameter, which is an object literal. The type property of this object will be set to Office.EventType.ItemChanged. When the event is called, the Office.context.mailbox.item object is already updated to reflect the currently selected item.

function itemChanged(eventArgs) {
  // Update UI based on the new current item.


The implementation of event handlers for an ItemChanged event should check whether or not the Office.content.mailbox.item is null.

// Example implementation.
function updateTaskPaneUI(item) {
  // Assuming that item is always a read item (instead of a compose item).
  if (item != null) console.log(item.subject);

Register the event handler

Use the Office.context.mailbox.addHandlerAsync method to register your event handler for the Office.EventType.ItemChanged event. This should be done in the Office.onReady function of your task pane.

Office.onReady(() => {
  $(document).ready(() => {
    // Set up the ItemChanged event.
    Office.context.mailbox.addHandlerAsync(Office.EventType.ItemChanged, itemChanged);

Task pane pinning in multi-select

In Outlook on the web and new Outlook on Windows (preview), when the task pane of an add-in that implements the item multi-select feature is opened, it's automatically pinned to the Outlook client. It remains pinned even when a user switches to a different mail item or selects the pin icon from the task pane. The task pane can only be closed by selecting the Close button from the task pane.

Conversely, in classic Outlook on Windows and Outlook on Mac, the task pane of a multi-select add-in isn't automatically pinned and closes when a user switches to a different mail item.

Deploy to users

If you plan to publish your Outlook add-in to AppSource, and it's configured with a pinnable task pane, your add-in content must not be static and must clearly display data related to the message that is open or selected in the mailbox. This ensures that your add-in will pass AppSource validation.

See also

For an example add-in that implements a pinnable task pane, see command-demo on GitHub.