Modifying Running Code in Xcode Fix (found in the 'Run' menu)

I am attempting to use the 'Fix' command found in the 'Run' menu in Xcode to modify my running code without having to rebuild. I have read apple's documentation on it but following their 'typical fix-and-continue workflow:' (http://developer.apple.com/library/mac/#documentation/DeveloperTools/Conceptual/XcodeDebugging/230-Modifying_Running_Code/modifying_running_code.html) doesn't seem to be working for me...

Here is what i am doing (from scratch): - create view-based project in Xcode - create click event to trigger a function that just logs some output - run in simulator with debugger (command-Y) - click 'pause' in the debugger. - add another log (or some other simple change) to the function - save modified code - select '开发者_如何学编程Fix' from the 'Run' menu - click continue and click button

The added log doesn't appear...

Not an answer, per se, but this "Fix and continue" system is disappearing in XCode 4. I wouldn't invest a lot of time in learning to use it, or developing a debugging strategy around it.