TOOLINFO ti = m_toolInfo;
ti.uFlags = (uint)TTF.TTF_TRACK;

IntPtr dwPos = (IntPtr)WindowsAPI.MAKELONG(position.X, position.Y);

WindowsAPI.SendMessage(hWnd, (int)TTM.TTM_TRACKPOSITION, 0, dwPos);
WindowsAPI.SendMessage(hWnd, (int)TTM.TTM_ADDTOOLW, 0, ref ti);
WindowsAPI.SendMessage(hWnd, (int)TTM.TTM_TRACKACTIVATE, 1, ref ti);

IntPtr hWnd = this.Handle;

TOOLINFO ti = new TOOLINFO();
ti.cbSize = (uint)Marshal.SizeOf(ti);

if (WindowsAPI.SendMessage(hWnd, (int)TTM.TTM_GETCURRENTTOOLW, 0, ref ti) != 0)
{
   if ((ti.uFlags & (uint)TTF.TTF_TRACK) != 0)
   {
      WindowsAPI.SendMessage(hWnd, (int)TTM.TTM_TRACKACTIVATE, 0, ref ti);
      WindowsAPI.SendMessage(hWnd, (int)TTM.TTM_DELTOOLW, 0, ref ti);
   }
}