Add-in taskpane panel area still visible after add-in closed

[joelfmrodrigues]

Provide required information needed to triage your issue

Your Environment

• Platform [PC desktop, Mac, iOS, Office on the web]: PC Desktop
• Host [Excel, Word, PowerPoint, etc.]: Outlook (new)
• Office version number: latest
• Operating System: Windows 11
• Browser (if using Office on the web): NA

Expected behavior

When taskpane closes, UI should reliably adjust to take the space previously taken from the task pane

Current behavior

Most of the time the UI adjusts to take back the space left empty by closing the task pane, but not all the time.

Steps to reproduce

1. Open an email from Drafts folder
2. Open a task pane add-in
3. Pin the add-in
4. Click on Send Items
5. UI space previously used by the add-in is left unused as per the image below

Useful logs

• Console errors
• Screenshots
• Test file (if only happens on a particular file)