The CloneFamilyStyle command replaces the current family style with its clone. The clone will be registered in the FULL_STYLES list and optionally in the AUTO_STYLES list, just like the model family style. The clone and the original styles are additionally locked to avoid their automatic recycling by Document::PurgeAutoStyles.
style -> [ a b ]
becomes :
style -> [ a b ] stylei' -> clone = [ a' b' ] DocManager::SetFamilyStyle (clone)
After undoing :
style -> [ a b ] scratch : stylei', stylei' -> clone = [ a' b' ] DocManager::SetFamilyStyle (style)
After redoing :
style -> [ a b ] stylei' -> clone = [ a' b' ] DocManager::SetFamilyStyle (clone)