/// <summary>
/// Remove paths that don't exist or are listed multiple times
/// </summary>
private void Clean_Click(object sender, RoutedEventArgs e)
{
lock (stateLock)
{
var sp = SystemPath.Select(_ => _.Path);
var up = UserPath.Select(_ => _.Path);
var cp = sp.Concat(up);
var s = sp.Where((p, index) => p.Exists && !sp.Take(index).Contains(p));
var u = up.Where((p, index) => p.Exists && !cp.Take(sp.Count() + index).Contains(p));
SetPaths(s, u);
}
}