Given that we have been encouraged to place the titles into the documents, might it be best to not actually delete the text that gets used as a title, when using “Split Document at Selection with Selection as Title” feature? It could, as an alternative, simply highlight the selected text – essentially preserving the selection between states – giving the user the ability to quickly delete it if that was their preference.
The idea is that you might import a long document in which you have placed titles just as a reference for yourself which you would no longer need in Scrivener. As it is, if you want to keep the title, you could always split document at selection as normal and then select the title and then do a “Set selection as title”… Dunno. I’ll mull it over.