View Downloads instead of REST server running ...

Using VS 2017 15.6.3  following >NET CORE 2.0 REST API tutorial.

https://docs.microsoft.com/en-us/aspnet/core/tutorials/first-web-api

Every time I start the service it launchesthe window View Downloads and closes the  Rest URL window. I can open and view the JSON response but I dont see how to test any other features on the URL because browser window has closed. If I select close to the view downloads window the instance stops...

Any ideas on what to configure ?

Thanks Andrewcw