User Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:61.0) Gecko/20100101 Firefox/61.0 Build ID: 20180704194937 Steps to reproduce: My thunderbird Inbox is ordered by the Date field so that all new emails should appear at the bottom of the list, together with their complete thread. Actual results: When receiving new emails, they may appear anywhere in my Inbox. On the left-hand side, the ordering of the inbox can be seen the bottom emails is from 13:41, while the last email arrived 16:47. Only when clicking twice (last dates first, last dates last) on the Date header, the sorting is correct, as shown in the right-hand side of the attached figure. Expected results: New emails should automatically be put into the correct order without the need to reorder. This was the case until thunderbird 60.

Your screen shot is showing more than inbox. Is it a virtual folder?

Yes, you are right, my Inbox is a unified folder of 2 mail-accounts, combining both outgoing and incoming mails.

I am also now seeing this bug since upgrading to Thunderbird 60 (1:60.0+build4-0ubuntu0.18.04.3 from the thunderbird-next PPA running in KDE neon Bionic). The issue does seem to only affect unified folder view.

Sam problem here, with saved search folders on thunderbird 60.2.1 (64-bit)

Similar, but not the same problem here since the update to 60.3: I have two accounts joined in a unified INBOX folder. New messages do appear at the bottom of the list. However, new messages which are in a threaded conversation do move the whole thread to the top of the window above the oldest message. - This does not happen in the individual INBOX folders of the two accounts, only in the unified INBOX. - This does not happen if view is switched to "unthreaded" . - The behavior persists even if all add-ons are disabled and after computer restart. Windows 7 Pro / Thunderbird 60.3.0 (32-bit)