Is there a Visual Studio 2019 way to combine solutions?

Question

It used to be that when I would go to the open project/solution dialog, I would get:

But now in VS 2019, these options are gone. How do I perform this same task in 2019 (dump all the projects from one solution into the other)?

Answer 1

I was just about to post my question when I had an idea, and it turns out to be the answer:

1. In the Solution Explorer, right-click on the currently-open solution (the one you want to dump projects into).
2. Add->Existing project:
3. Change the file type/extension drop-down to Solution Files (*.sln).
4. Select the solution to import projects from and import away!