Hi. I came with two answers to you.
At my opinion there are 2 approaches to do it.
In core of first lies implementation of your own WPF Window style via Templating and Stylization.
Second one, relies on WinApi methods and rerquire profound knowledges in P\Invoke in .NET enviroment.
So i would recommend to you use first approach, in terms of it flexibility.
I think this link can help you:
Wpf window template