How do I create a new flipbook without overwriting an existing one?

I know one way is to open options popup (Flipbook with New Settings) and type in a name for Flipbook Session Label.

But, I have seen someone use a top-rght corner icon to do this in the flipbook, however I can't find this in my version (18.5). Is it still an option I can find somewhere, maybe in a display option menu?

Try the disconnect button on the top right. It looks like (*). There's apparently a shortcut too, Alt+Shift+I, but it doesn't work for me.

I don't see that and that shortcut does not work on my Mac -- no Alt key for a start.

This is the MPlay on my version, I don't see an option to not overwrite:

https://ibb.co/4TKJPR4 [ibb.co]