I recently upgraded Thunderbird from ver 2.0.0.24 to ver 45, at first I had all my emails in a list down the screen. Now are in tabs at top of the screen which makes it very difficult manage, for example to find a particular email. How can I revert to having all my emails in a list going down the screen? If this is not possible, how can I safely revert to thunderbird 2.0.0... without losing some or all my mail messages? Thank you, Graham Daniell