Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

At ViewSort byGrouped By Sort you can activate the grouping of your mails by the chosen sort method. E.g. when you select the sort method "Date", you get groupings like "Today", "Yesterday", "Last Week", ….

Screenshot of a folder with grouping by date

These groups can be (un)folded by clicking at the little triangular icon (in some themes it seems to be a plus sign).

I observed several Thunderbird users that tried to unfold a group by double-clicking at the group heading (e.g. "Today") instead of single-clicking the little icon. I think this is natural behavior known from many other applications. However, Thunderbird won't unfold the group. Quite the contrary: Thunderbird opens all mails in this group. This creates two problems:

  • all these mails are now marked as read
  • it may take some time to close all the tabs again

After "Two Weeks" the next group heading is "Old Mail". This group might hold several thousand mails. You can imagine that it's no fun to see all these mails opened accidently.

Is there a (config) setting that disables this behaviour? If not, is there an add-on?

When the user double-clicks the group heading, the group should (un)fold (and never open all mails).

I filed an issue:

share|improve this question
up vote 0 down vote accepted

In PreferencesAdvancedConfig Editor… you can set the option mail.operate_on_msgs_in_collapsed_threads to false (thanks, Joe Sabash).

This setting seems to "eliminate[s] the message summary in the preview pane", too.

Now nothing happens when you double-click at the group heading. Still missing is the functionality to (un)fold the group by double-clicking. The issue is there:

share|improve this answer
I'll mark this as fixed until someone provides a better solution. – unor Oct 30 '12 at 13:05

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.