I just discovered a method of drag and drop with the BBM.
While the BBM is running just open up the BBM again, you get two BBM’s running and you can drag and drop between them. In the one BBM mode if you drag and drop you loose the source file because you move it. In the 2 BBM mode it just makes a copy and your source stays where it is. Just keep track of which of the BBM;s you have to save when your working in the same project.
You don’t need to do that. There is a copy function. You can right click the part you want and choose Copy. Then you can hover over the part where you want it to be (The … or the song part will be highlighted) You can then Ctrl+V to paste the part.
Or, you can use the option-drag on macOS to copy; alt-drag on Windows