Perform the following actions field height reduces

High Sierra 10.13.6, as I add more conditions to a Rule, the height of the “Perform the following actions” field shrinks until it’s unreadable. Any ideas?

This is caused by a longstanding Apple Mail bug (not related to SpamSieve). It should help (temporarily) to close and re-open the rule editor sheet.

Ah,

I made the old correlation = causation error. I tried a bunch of things, including individual replacements parts of Spamsieve support files from backups, but the Apple Mail Rules only started working AFTER I turned iCloud syncing for Apple Mail off, and THEN copied another backup but this time for the ENTIRE MailData folder in ~/Library/Mail/V5/.

So I wrongly assumed that was the cause.

Next time I’ll try (temporarily) closing and re-opening the rule editor sheet.

Many thanks

JD