User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.9) Gecko/20071025 Firefox/2.0.0.9 Build Identifier: version 2.0.0.6 (20070728) The location of the columns, which columns, and the sort option is reset randomly when 1 user exits Thunderbird. For example, lets say 'Sender' is set as the first column to the left, and date is the next column. When exiting Thunderbird and returning later (either next day or next minute) the column order has been reset, so Sender might be third and date might be sixth. Reproducible: Always Steps to Reproduce: 1.Set column order 2.Exit thunderbird 3.Column order has been reset Expected Results: Column order should remain as it was when the user exited the application. This is an annoyance to the user.

Sounds similar phenomenon to Semonkey Bug 384712. What is set in mailnews.ui.threadpane.version?

I see this same behavior in Eudora 8 running on Vista. Customized toolbar buttons also revert to default on program restart. I would classify this as more than "minor".

This was fixed (at least Joey's problem) on trunk 2007-09-05 see bug 384712 comment 20. But it won't bee coming to version 2.