Previously actions remained linked after duplication, now this is based on the User Preferences (PreferencesEdit.use_duplicate_action).
note: default is ON here, so this changes default behavior of separate operators.
First intuition was to respect _all_ preferences here (e.g. also duplicating materials if chosen in the User Preferences) but after consideration this is probably not what the User would expect from such modeling opertions (e.g. separate by loose parts resulting in possibly many duplicate materials)