Using the new save current song as startup song means that the song saved will be reloaded every time you press the start a new song in the disc-op and want a blank rns.
I’m pretty sure that’s the intended behaviour and how it has worked for 1.281 (although the button wasn’t there then) 
Seems a bit odd to me as every time you want a new rns (if you are using this option) you have no way to get it unless you have a saved blank rns.
Just tried the delete all in Advanced Edit with the same result. Would be better IMHO if it wasn`t like this.
it makes complete sense if you think about it
some ppl use pre made templates
w/ the samples in them
dsps already set on tracks…etc
I guess the name “startup song” is a bit confusing.
What would you use the startup song to if not to save a bland rns? That’s the idea of it.
Maybe so. Its not a feature I have used personally and was more bug testing the new features.
The reason I posted as a bug report was that by saving a song with this feature I was then stuck with that song at every new delete all or start new song (a MIDI/VST rendition of Baker St.)
It seems to me that it would make sense to at least have a Clear default song next to the save under misc to undo mistakes.
Its not impossible to clear all patterns and unused instruments then clear the notepad info then go and clear any DSPs you had and collapse tracks down, but it would be nice to just do this with one button if you made the same mistake I did.
Apart from that from what you have both said then it does make sense to at least keep start an new song as it is, for what seems like quite a useful feature from this conversation.
For anyone who wants to remove a mistake save like the one I did, I found your song is saved as DefaultSong.rns in the renoise folder. You just need to delete this to get rid of your unwanted save.
this was the same (implicitly) in 1.281 too: defaultsong.rns, if present, was loaded at startup (ps: if you want to post a bug report, there is a specific forum section)
did but it was moved by someone 