I thought it would be as easy as copy/paste, but I can’t get it to work. I’m trying to add a few frames at the end of my movie for the credits. And my credits are in another shotcut file. How do I add the frames from one playlist to another?
Here’s what happens… when I drag the 2nd file onto my playlist, it gets added as v1… right on top of my other big file. Clearly, I’m doing something wrong… 
Not sure what you are doing to get this, do the two files have the same name? You need different name.
Example start Shotcut, click on playlist , it is empty. Open file explorer to folder that has first file, drag file to playlist. Go to folder for second file drag it to playlist, must have different name. You should now see two files in playlist. Click on timeline, it should be empty. Drag first file to timeline, you should see it there. Drag second file to beyond the end of the first file on the time line, you should now see two files on the timeline. You may have to move the second file to the left a bit, so it is just touching the first file, it should snap to it and you should be good to go.