Resizing controls dynamically efficiently

Instead of Suspend/ResumeLayout you could try using SetRedraw. 

    public class RedrawLock : IDisposable
    {
        #region External Method Definitions

        [DllImport("user32.dll")]
        static public extern UInt32 SendMessage(IntPtr hWnd, UInt32 msg, UInt32 wParam, UInt32 lParam);
        [DllImport("user32.dll")]
        static public extern UInt32 RedrawWindow(UInt32 hwnd, UInt32 lprcUpdate, UInt32 hrgnUpdate, UInt32 flags);
        #endregion

        #region Members and Constants
        
        const int WM_SETREDRAW = 0x000B;
        Control window = null;
        
        #endregion

        #region Constructor

        public RedrawLock(Control winToLock)
        {
            window = winToLock;
            SendMessage(window.Handle, WM_SETREDRAW, 0, 0);
        }

        #endregion

        #region IDisposable Members

        public void Dispose()
        {
            SendMessage(window.Handle, WM_SETREDRAW, 1, 0);
            window.Refresh();
            RedrawWindow(0, 0, 0, 0x181); //168, to redraw the desktop so remnants of this form disappear.
        }

        #endregion
    }

 Wrap the code in a using (new RedrawLock(this)) {} block.