WPF video is displayed on one monitor out of three, how to expand the image to all?

Question

WPF

There are three monitors connected by nvidia surround, here is the code:

<Window x:Class="Motion.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:Motion"
        mc:Ignorable="d"
        Title="MainWindow" 
        WindowState="Maximized"
        WindowStyle="None"
        KeyDown="OnKeyDownHandler"
        Loaded="Window_Loaded">
    <Border Background="Black">
        <MediaElement Name="myMediaElement" 
                  Volume="1" 
                  LoadedBehavior="Manual"
                  UnloadedBehavior="Manual"  
                  Stretch="Uniform"
                  MediaEnded="myMediaElement_MediaEnded"/>
    </Border>
</Window>

Start is carried out

myMediaElement.Source = new Uri(_paths[0]);         
myMediaElement.Play();

But the image is only on one monitor. Tried on winForm + vlc , but it's the same there.