If I log in and just change the sort order of Inbox to "by sender", refreshing the browser page has no effect. The sort order stays at "by sender". I can do any of the following actions and the Inbox sort order stays at "by sender" (or however I set it):
- Refresh the browser page
- Change to a different folder, then return to Inbox
- Log out of Fastmail, then log back in
- Log into Fastmail with a different browser (Chrome vs Firefox)
- Log into Fastmail with the iOS app
It would be interesting if your account does not act this way.
Bill