Custom nested container control

Question

I'm writing a custom control which consists of a FlowLayoutPanel nested in a normal Panel. The FlowLayoutPanel is internal to the class, and shouldn't be able to be viewed by the designer (unlike a Tab, which has its individual properties exposed.) Any control the designer adds to the Panel should instead be added to the FlowLayoutPanel. Here's what I have so far:

public class SlidePanel : Panel
{
    private FlowLayoutPanel _panel;

    public SlidePanel()
        : base()
    {
        _panel = new FlowLayoutPanel();
        Controls.Add(_panel);
        _panel.Location = new Point(0, 0);
        _panel.Size = base.Size;
        _panel.Anchor = AnchorStyles.Bottom | AnchorStyles.Top;

        ControlAdded += new ControlEventHandler(SlidePanel_ControlAdded);
    }

    void SlidePanel_ControlAdded(object sender, ControlEventArgs e)
    {
        Controls.Remove(e.Control);
        _panel.Controls.Add(e.Control);
    }
}

This works for controls added during runtime, but when I try to add a control during design time, it either says 'child' is not a child control of this parent. or adds the control the the form instead. I'm assuming there's a cleaner, nicer way to accomplish this?

---

Test of Flynn1179's suggestion:

public class SlideControl : FlowLayoutPanel
{
    private const int SB_HORZ = 0x0;
    private const int SB_VERT = 0x1;

    [DllImport("user32.dll")]
    private static extern int SetScrollPos(IntPtr hWnd, int nBar, int nPos, bool bRedraw);
    [DllImport("user32.dll")]
    private static extern int GetScrollPos(IntPtr hWnd, int nBar);

    public SlideControl()
        : base()
    {
        this.MouseMove += new MouseEventHandler(SlideControl_MouseMove);
    }

    void SlideControl_MouseMove(object sender, MouseEventArgs e)
    {
        HScrollPos = e.X;
        VScrollPos = e.Y;
    }

    protected int HScrollPos
    {
        get { return GetScrollPos((IntPtr)this.Handle, SB_HORZ); }
        set { SetScrollPos((IntPtr)this.Handle, SB_HORZ, value, true); }
    }

    protected int VScrollPos
    {
        get { return GetScrollPos((IntPtr)this.Handle, SB_VERT); }
        set { SetScrollPos((IntPtr)this.Handle, SB_VERT, value, true); }
    }
}

Answer 1

Have you considered having SlidePanel inherit directly from FlowLayoutPanel rather than contain one?