Hi @Cooeeeee
I see. The point of my post was to simplify @Fernando-Sorensen’s method, because although ingenious, it requires several steps. The basic idea was to do everything without additional windows, be it a second editor, the column editor or a search window, that would block or cut off the flow of the operation.
The only thing that the BetterMultiSelection plugin is good for in my approach is precisely to insert the blank lines, an operation that standard multiselection cannot do - see @Alan-Kilborn’s post below - . But if the text already has blank lines interleaved, then the plugin is not necessary and, as your .gif shows, line interleaving can be done directly with standard multiselection.
Which is the best method? For the reasons detailed above and because I have nothing against third party plugins either - in fact, I think they are a great addition to Notepad++ and heavily use them - I still prefer mine, but I have no objection to people using the one they find best.
Thank you and, as always, have fun!