Have you found a solution to this yet? I have built a mobile app using Flex 4.5.1 and in testing it for release have found the same problem that you are refering to hear, however, in profiling the application against this problem I am finding that it is not in fact returning to the first view when the already selected tab is pressed but is rather creating a new instance of the view and adding it to the stack of that particular view.
I have been unseccesful as of yet to find a solution or the reason for this behavior and would appreciate very much hearing about any solutions you or anyone else has found, Thanks
No sry, i didn't find a solution for that. Lucky for me the requirements of my project changed a little bit so that a tabbed navigator was no longer an option and so i no longer needed to worry about this problem.