@TotalNoob69 Basically I originally made a study for the Sicilian with a chapter on the Taimanov and a chapter for the Kan. Those chapters each quickly became very bulky obviously, so I wanted to split them out further into say a chapter for 5. Bd3 and a chapter for 5. Nc3 in the Kan.
Now I have to create a new chapter and play out the moves again one by one to get the same line I already had in my Kan chapter. If I could right click on a move/line and choose "Copy to new chapter" or something to that effect, I could easily create new chapter for particular lines if they end up becoming bulkier than I had originally thought.
I usually start with a single chapter for something without knowing how deep I'll go into that line so it doesn't make sense yet to make multiple chapters. I often only realise that later when I figure out I like a certain line and want to analyse it deeper.