STR (Using the Browser Debugger but probably same for content debugger): Set a breakpoint in a nested function. When the breakpoint is hit, move up the call stack to the caller. Add a watch variable ER: The watch variable is evaluated and the current scope doesn't change. AR: The current scope is changed and then the watch variable is evaluated. This breaks some things. First, if you are trying to evaluate a local variable in a caller then the evaluation will fail saying that the reference is undefined. Second, it is annoying that the scope changes because now you have to go back up the call stack to continue debugging.