Build Warning. Disabling auto-resolution previews is not supported on iPhone OS versions up to 3.0

Question

This build warning has just appeared. I am building 3.1.3. Not sure what I did to trigger this. Does anyone know what this means?!?

CompileXIB Classes/RootViewController.xib
Disabling subview autoresizing is not supported on iPhone OS versions prior to 3.0.

Answer 1

Click the Info button in the xib main window and set iPhone OS 3.0 or iPhone OS 3.1 for deployment.

Edit: Images!

(NB: they are from version 10.5 IB, but IIRC version 10.6 is the same or close to it.)