I have asked this question on Mozilla Forum but never got a reply. When I navigate away from the inbox, for example to write an email I often find it difficult to get back to the inbox. Sometimes I have to close Thunderbird down and relaunch to continue work, at other times I just happen to land on a button that takes me back. I suspect this is just a simple thing that I have missed out on somehow. What is the straightforward way to get back to the inbox?