User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/94.0.4606.61 Safari/537.36

Steps to reproduce:

Brand New Macbook Air with new M1 chip. Latest Mac OS Big Sur 11.6. I have 5 email accounts. Select Unified Folders. All works fine. Right Click on Inbox (in Unified Inbox), Properties, Choose (on the right hand side), untick the inbox from the email account I don't want to be included in the Unified Inbox, click ok.

Actual results:

The 'Edit Saved Search Properties for Inbox' window immediately greys out and I can't click on update so have to exit Thunderbird and it then doesn't save the change I made (removing one email account inbox from Unified Folders Inbox)

Expected results:

It shouldn't grey out and should allow me to click on Update to save the changes. This works fine on my Windows PC and my old MacBook Pro.

I tried version 91 and 93 and it still has the same error.

Thanks. This will be bug 1699514