I work on an add-in for Microsoft Outlook, and recently we’ve received reports from some users that they can no longer click on buttons in the taskpanes of add-ins. Other add-ins, not just ours, have been affected by this issue. Affected users can still open the taskpane without issue. Our taskpane web view loads correctly, but then any clicking inside the taskpane has no effect. We are not seeing console errors when this happens.
To help narrow things down further: we’ve seen this issue occur in Outlook 2019 and Outlook for Microsoft 365 MSO with Office 365 accounts so far. We’ve seen this issue happen when the taskpane is opened from Compose view. One affected user was using Outlook 2019 version 16.0.13127.20266 (32-bit). Affected users have been running Windows 10, version 2004. A team member was able to reproduce the bug by updating to version 2004, but the bug disappeared for them after a subsequent system update on the same version 2004.
Has there been any recent change to add-in taskpane behavior that could be causing this issue?
This issue was fixed, and the fix should be available in Windows build 19043.1266 or later. Note that it is the Windows Build that matters, not the Office build.