WPF Always On Top

This won’t work 100% of the time, but it will improve the situation somewhat. You can set Topmost = true in the handler for the Window.Deactivated event:

private void Window_Deactivated(object sender, EventArgs e)
{
    Window window = (Window)sender;
    window.Topmost = true;
}

The Deactivated event will be called whenever your application loses focus (often when another application requests to be Topmost) and so this will reset your application on top after this.