|Mitch Moody 2020-08-05 09:26
I had a user here with Ultramon enabled and they were seeing a bug where Outlook 365's Scheduling Assistant would no longer change the message window from the message details as long as Ultramon was running. As soon as they closed Ultramon, Scheduling Assistant would then work correctly.
Windows 10 v1909
Ultramon version 3.4.1
|Christian Studer 2020-08-06 02:53
A couple of other users reported the same issue, disabling window buttons for Outlook via UltraMon Options > Compatibility was the only way to fix the problem.
Unfortunately I haven't been able to reproduce this myself, my Outlook 2019 installation for some reason doesn't have the scheduling assistant.
Christian Studer - www.realtimesoft.com