How can I apply a style to the Window Control in WPF?

I am setting a style for the Window in the App.xaml like such:

<Application x:Class="MusicRepo_Importer.App" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:System="clr-namespace:System;assembly=mscorlib" StartupUri="TestMaster.xaml">
    <Application.Resources>

        <Style TargetType="Window">
            <Setter Property="WindowStyle" Value="None"></Setter>
        </Style>

    </Application.Resources>
</Application>

With which I basically want every Window to have its WindowStyle's property value set to None (to remove the default windows frame and border); But it is not working.

What am I missing here?