How to change a Visual Studio project type?

Question

I finally figured out that Visual Studio keeps track of how you create a project (in other words which project template you select initially) and filters your options later

Answer 1

I needed to add WPF support to a project of type "Class Library (.NET CORE)" in this way:

• edit YourProject.csproj (double click on it) and modify to
• add true in the group
• rebuild YourProject

Now you can add a WPF Window