I'm trying to test certain code in my application so I am commenting out parts.
Commenting out parts of the code doesn't always have an effect because my code still runs as if it's not commented out.
Lately FB4 has been squirrly in not compiling my code, because changes I make have no effect. Quitting/restarting FB doesn't fix the problem. Clean and refresh don't fix the problem either. And some times it loses the Flash debugger tool as well.
Can you post your flash builder log in workspacedir/.metadata/.log?