You can do that now but you need to open another instance. (as I see Jim has showed)
Copy chord from one instance to another has been requested and maybe implemented soon hopefully.
At the moment you need to File > Import > Import MGU/SGU Song then select chords number of bars from > to.
You can copy paste Audio track sections from one instance to another.
You can Drag n Drop Audio/Midi bars or whole track from one instance to another.