Keyboard Focus Never Enters Add-in Pane

[nsimoncelli-virtru]

Keyboard focus never enters add-in task pane, breaking sequential navigation (WCAG 2.4.3)

Your Environment

• Host: Outlook
• Browser: Chrome (latest)

Expected behavior

When tabbing through the Outlook Web interface using keyboard navigation, focus should move sequentially from Outlook controls (e.g., Reply button, Forward button) into the add-in task pane. The user should be able to:

1. Tab to the "Close add-in pane" button in the pane header
2. Tab into the iframe and reach all interactive elements inside the add-in
3. Navigate through the add-in content in logical sequential order

Current behavior

When tabbing through the Outlook interface, focus never enters the add-in task pane. Instead, focus jumps back to the top of the page, breaking the expected sequential tab order. The "Close add-in pane" button, the iframe, and all interactive elements within the add-in are
completely unreachable via keyboard navigation.

Steps to reproduce

1. Open Outlook Web (https://outlook.live.com/mail/)
2. Open any email
3. Activate any Office add-in (task pane appears on right side)
4. Tab through the interface using keyboard only (no mouse)
5. Observe that focus never enters the add-in pane and instead jumps to the top of the page

Provide additional details

The add-in pane iframe (FlexPane_AddinsPane) is not included in the parent Outlook page's sequential focus order. Add-in developers cannot fix this issue because the iframe structure and focus management are controlled by the Outlook Web/Office.js platform, not by add-in
code.

HTML structure:

<div id="FlexPane_AddinsPane">                                                                                                                                                                                                                                                       
  <div class="...">                                                                                                                                                                                                                                                                  
    <button aria-label="Close add-in pane" data-is-focusable="true">...</button>                                                                                                                                                                                                     
  </div>                                                                                                                                                                                                                                                                             
  <div id="CustomFlexPane_AddinsPane" role="region">                                                                                                                                                                                                                                 
    <iframe title="Office Add-in" sandbox="..." src="..."></iframe>                                                                                                                                                                                                                  
  </div>                                                                                                                                                                                                                                                                             
</div>                                                                                                                                                                                                                                                                               

Context

Keyboard-only users and assistive technology users (screen reader users, users with motor disabilities, etc.) cannot access or interact with any Office add-in content. This makes add-ins completely unusable for these users and violates WCAG 2.4.3 Focus Order accessibility
requirements. This is a critical accessibility barrier that prevents users with disabilities from benefiting from Office add-in functionality.

Reference:

• WCAG 2.4.3 Focus Order: https://www.w3.org/WAI/WCAG22/Understanding/focus-order

[github-actions]

Here are some similar issues that might help you. Please check if they can solve your problem.

• Impossible to reach/move focus back to Word add-in with keyboard navigation  #4549

---

Possible solution (Extracted from existing issue, might be incorrect; please verify carefully)

Currently this functionality is not supported yet. If you have this need, I would like to suggest you go to https://techcommunity.microsoft.com/t5/microsoft-365-developer-platform/idb-p/Microsoft365DeveloperPlatform to ask a new question. Feature requests on it are considered when we go through our planning process.

Reference:

• Impossible to reach/move focus back to Word add-in with keyboard navigation  #4549 (comment)

Powered by issue-sentinel

[AlexJerabek]

@emmasab, could you please investigate?