This is similar to uninstalling from Xcode 4, but it is not very necessary, since Xcode 4 integrates the editor directly with IB. In any case, the function has never worked so well in Xcode 3 IMO.
In Xcode 4, display the title for your object by choosing your object and View> Editors> Helper. Now drag the control from the object you want to include in the header. This will automatically create an output or action and link everything at once.
See the Xcode 4 Migration Guide for more information.
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