i like the feature that usual organization top-level packages (e.g. org.apache) can be snipped away by going 'Settings->Project Settings->Modules->Add ContentRoot' then choosing package-prefix.
this works fine for new projects when package and classes do not exist already.
though when setting this after packages and classes already have been created, the top level packages aren't snipped away merely the package prefix is prepended to the existing ones.
so how do i workaround/solve this problem?