In the past, when the search results were returned and I clicked on a message to read it and then clicked the back button, it would return to the search results. Now the back button does nothing. How do I return to the search results after clicking on and reading a message in the results?

Correction: It appears that the back button works until you view a message in the results and then while viewing that message, click on the thread button on the message footer (view all messages in this thread) to view the entire thread. From that point on, the back button no longer works and you can't get back to the search results.