Parent Form ->
  Child Control 1 ->
    Child Control 2 ->
      Custom Control

protected override void OnLoad(EventArgs e)
    {
        base.OnLoad(e);

        _originalParent = Parent; // member var
        _originalLocation = Location; // member var
    }

    protected void SetParentToRoot()
        {
            var p = Parent;
            if (p == null) return;
            while ((p?.Parent ?? null) != null)
                p = p.Parent;

            Parent = p; // this line will cause the app to hang

            // determine the screen location of the control based on the original parent
            var screenPoint = _originalParent.PointToScreen(_originalLocation);

            // set location
            Location = p.PointToClient(screenPoint);
        }

    protected void RestoreParent()
    {
        Parent = _originalParent;
        Location = _originalLocation;
    }