A features that I liked in GMail was that when an email arrived that was a reply to an earlier email, Gmail would display all of the previous emails along with the new one in a single thread in my inbox. Importantly, GMail would display emails in the thread even if they had been previously archived.

Now I am using Thunderbird to access GMail. Thunderbird 3.1 supports Gmail-style archiving and threads, but it only dispalys messages in threads if they are in the same folder. If I have an email thread with someone and I archive that thread and then a new message arrives, only the new message appears in my inbox. This is really inconvenient. Before I could archive a thread without worrying that I would lose the contents of the thread should a new email arrive. Now, if an email arrives I must go through the All Mail box and find the rest of the thread.

Is there any way to set Thunderbird so that it will automatically show the archived emails in the thread along with the new one? Perhaps there is some way to automatically un-archive the rest of the messages? Maybe this is an add-on waiting to be written?