Why don't I need to implement these abstract functions in C#?

I am extending an abstract class Scene:

class IntroScene : Scene
{
    //
}

As you can see, it doesn't do anything. The abstract class Scene has abstract functions:

public abstract void LoadContent(ContentManager content);

But, it's not complaining to me that I should implement them. Why not? This is what I'm used to.

I'm doing this in Visual Studio 2015, using the .NET framework 4.6.1. Until recently I only worked in .NET 4.0. Is this a change in the new C# 6.0 features, or am I missing something?