Dear tybg....
Firstly, you are way beyond kind to help like this and explain these things, and to volunteer to keep helping. And, due to your attention on this with me, I have had the ability to presevere thru all this...OMG. So tons of thanks for that too.
1. www.icloud.com / Preferences / Gear:
I guess the main point I am making here is that if one chooses those folders, like that: thru the gear / preferences, my version of icloud does not look like what you are showing....
Means: there is a line of text under those choices which reads 'messages will be deleted from the trash after 30 days'. (your image does not have that text there...odd)
(It seems 'sent' messages are not deleted by default like I thot, even from the default folders in www.icloud.com.
it is only if there are any messages in the Trash default folders. That does get deleted.)
Does this make sence?
I have found that since I have not chosen the new folder for trash, in the above window, (but left it set to the default trash folder, and instead chose via Mac Mail / Mailbox behaviours, the new Trash folder I made which is listed under Folders that now my trash is not getting deleted anymore.
If i do choose in that window above, the new Trash folder I made, then it changed locations in the left column in icloud.com, and popup up into the top, to the default folders areas. It did not remain in the area under 'Folders'....just saying..
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2. Your kind points:
Also I can see you have not set up any gmail account or yahoo as such that is configured .
right, in my mac mail account I am not receiving any gmail or yahoo email, right. (I get way too many emails from those accounts - tons of spam-so just view them online.)
I am only receiving this one IMAP account: icloud (via my Mail account)
It depends upon the internet service provider also , in how many days they delete the mails from trash folder , however you have saved the settings in mail box behaviours
Right, good point, well, in MacMail, did set the trash to NEVER delete as you mention.
3. Mavericks:
Just to stir it up a bit more, in my other computer, running Mavericks, it is even different.
Same set up in icloud is working.
But one has to choose in Mail / Mailboxes: 'Use this mailbox as' then choose trash etc from the options on the left under icloud. plus the settings in Mailbox behaviours is quite different, meaning only 1 option: choose leave on server or get on my mac.
Thanks again dear tygb (thank you, Great Britain?). You are a true knight in shining armour.
Warmly,
HeavennOnnEarth
me