When you say "Flash Builder Mobile project", are you using Flash Builder 4, or did you mean ActionScript Mobile Project in Flash Builder 4.5? If it's FB4.5, AS mobile project, there's an app descriptor file, it'll be called something like myproject-app.xml. If you look in there, set to Source view, you should find this line: <!-- <fullScreen></fullScreen> --> You would need to put 'true' in there, and uncomment the line, to give you: <fullScreen>true</fullScreen> That should make the status bar hide.
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