As far as I remember, the same scenario works. Type System. and Visual Studio should show the Intellisense window with its contents. If it does not appear, you can try Ctrl + Space to make it appear.
If it still does not show anything, you may need to add the assembly reference in the DLL that contains this namespace to your project.
Obviously, if the namespace is System, you do not need to add a link, as it is already added by default.
Also relevant: View Object Explorer in Visual Studio.
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