I wish it wasn't so hard to transfer a screen shot here. I tried the other day but it gave me a pain. Anyway, I did upgrade to 10.12.5 the other day.
As far as following your instructions to move deleted messages to the trash, I don't have that option under mail behaviors. Next to the Trash Mailbox there, there is a dropdown box that says Trash. Under that it says "erase deleted messages:" Then there is another drop down box offering me a choice of erasing deleted messages after one day, one week or one month. But they are already gone so I never had to delete. I'll just live with it.
As far as the having to scroll side to side, I found it was because I had it in full screen (which hides the tool bar and I hate that) and made it too wide. I resized the window and it fits now. I'm just not used to that.
To clarify, when I click on an email to delete it, whether it's in the junk (goes straight to cyber space- I didn't know that) or from the inbox, it never ends up in the trash like it used to.
I also used to be able to delete mail from the trash by choosing Command-Shift-Delete in Mavericks and a few times in Sierra. That doesn't work anymore in Sierra (except now nothing ends up in trash in Sierra) but still works in Mavericks.
And while I'm on my rant, when reading posts here I have to scroll back and forth to see the whole line. Making text smaller doesn't fix it. This happened before but finally stopped. It's starting up again and is aggravating.
Is the Mail > Prefs > Accounts > Mailbox Behaviors > Move deleted messages to the Trash mailbox check-box checked for
each of your mail accounts?
command-shift-D has never failed to empty my trash mailbox in Sierra.
I've only had to scroll to read FTM posts that included line-stretching links, but I can't recall more than one or two such posts in years.
I dunno... You've got an awful lot of issues for a pretty much pristine installation; I wonder if it would be worth your while to d/l and run the
macOS Sierra 10.12.5 Combo Update.
