How to drag a rectangle using GDI+?

Question

I am trying to implement a dragging of a simple rectangle using GDI+. My code is simply working by translating the graphics object to the new position and to draw a new Rectangle.

TransllateRectangle is called frequently whenever OnMouseMove event occur.

void RectangleContainer::TranslateRectangle(CDC *pDC, CRect newR, CRect   oldR)
{   
   Graphics graphics(pDC->m_hDC);

   DWORD ole = m_FillColor;
   BYTE rr = ((BYTE)(ole));
   BYTE gg = ((BYTE)(((WORD)(ole)) >> 8));
   BYTE bb = ((BYTE)((ole) >> 16));

   SolidBrush linGrBrush(
      Color(125, rr, gg, bb)
   );

   Rect newRectangle = Rect(newR.left, newR.top, newR.Width(), newR.Height());

   Matrix matrix;

   matrix.Translate(newR.left - oldR.left, 0);

   graphics.SetTransform(&matrix);

   graphics.FillRectangle(&linGrBrush, newRectangle);

   graphics.~Graphics();

}

My problem is that I could not remove old rectangle drawn in the old position properly. How can I achieve this please?