I think what you’re needing is two commands after you’ve selected the range:
- Copy (Ctrl-C, Cmd-C, etc.)
- EditMenu->Range->PasteTime (Ctrl-Shift-V on my system, but this may not be the default)
This inserts what you’ve copied at the start of the selected range and it all shuffles up, effectively duplicating the selection area. If you want to insert at the cursor then make sure you dont’ have a range selected. You can insert in a different place on the timeline by moving the range selection or cursor of course.
I use this method to change song arrangements, e.g. double choruses, add another verse, halve 2nd middle 8 to increase pace of song, add 2 extra beats for a pause etc. if I’m after testing various arrangements then I’ll use the arranger track and then flatten.