Global Deletion
 

Some time ago Fastmail made webmail deletions global by default, so all copies of the same email are deleted across all folders. It used to be possible to turn this off by turning-off the grouping of emails, but that doesn't seem to work anymore.

Am I missing some other way of turning-off global deletion, or have they now forced it on me?

I suspect that with the introduction of JMAP in the backend, the way messages are stored and managed may have changed in a way that effects deletion of individual messages. I would suggest a support request, asking about the behaviour change, and asking if there is a clean way of keeping the message in one folder while removing the same message from a different folder.

The only circumvention I can think of for now is to move the message back from Deleted Items to the desired folder after the delete. Possibly, rather than deleting the message, it may be possible to move it from the folder it is no longer wanted to Deleted Items. You could try it to see what happens.

Actually it looks like I was wrong. What I'm actually seeing is spams removed globally when I use 'report spam'. I thought the two things were linked, they aren't now, and perhaps they never were.

The reason I care is that I only allow a minority of my mail into my fastmail account, but I file everything into a folder that's used by getmail and I want the spam to train my own local spam filters.