I often find myself changing existing microflows and pages and ending up with more refactoring then I had anticipated. In those cases I usually want to preserve the old document for reference or a possible 'rollback' and test with the new version of the document. Usually I don't start of with a duplicate, which obviously would be convenient but not always. Therefore I'd like to have a 'Save as..' option when closing the tab so I can save the new version under a different name, maybe in a whole different module if need be.
Now I usually make a duplicate of the new version, rename it and revert changes on the original one. Hope you guys can relate!