Actually it appears the navigation bar is related to our new web server - what web server settings would cause a label / text box to appear at the bottom of the web browser?
We tested by copying over the compiled SWF files from our old web server to our new web server, and the bar didn't go away.
This bar appears to contain query string information specific to the Flex application and the TabNavigator position - for example:app=94d3&d9f1-selectedIndex=10&274b-selectedIndex=0app=94d3&d9f1-selectedIndex=10&274b-selectedIndex=1app=94d3&d9f1-selectedIndex=10&274b-selectedIndex=3app=94d3&d9f1-selectedIndex=5&274b-selectedIndex=0app=94d3&d9f1-selectedIndex=0&274b-selectedIndex=0app=94d3&d9f1-selectedIndex=7&274b-selectedIndex=0app=94d3&d9f1-selectedIndex=8&274b-selectedIndex=0app=94d3&d9f1-selectedIndex=6&274b-selectedIndex=0
We really need to get this resolved - our applications are practically unusable.
How can the same SWF behave differently on two different servers?
We've tried FireFox, Chrome, and IE on two different systems and the results are the same - if loading the SWF from server A all works fine, but if loading the SWF from server B then the text bar appears on the bottom affecting the application's scroll bars.
Ok I believe that we've found a solution - setting historyManagementEnabled="false" on the TabNavigator appears to have done the trick.