Mouse movement within CStatic/Picture box

Hello,

I have a picture box, in which I need to draw a rectangle when user
makes a selection by dragging the mouse.

I am able to capture the mouse click event in the picture box(by
deriving from CStatic and handled the
ON_STN_CLICKED event from main Form).

But I am unable to understand how to capture mouse drag/ draw a
rectangle over picture box when the mouse moves. (New to MFC
programming, Pls help, any tips on how to handle OnLButtonUp,
OnMouseMove events for CStatic controls!) I really appreciate any
help.

Heres the code of what I have right now:

CpictureBox.h
------------------------------------------------------------------------------------------------------
class CPictureBox : public CStatic
{
    DECLARE_DYNAMIC(CPictureBox)

public:
    CPictureBox();
    virtual ~CPictureBox();
    void SetBitmap(CString strBitmap);
protected:
        afx_msg void OnPaint();
        void ShowBitmap(CPaintDC *pDC);
        CString m_sBitmap;
        CBitmap m_bmpBitmap;
        BITMAP bm;
        CRect m_Rect;

    DECLARE_MESSAGE_MAP()
};

void CPictureBox::OnLButtonDown(UINT nFlags, CPoint point)
{
   m_Tracking = TRUE;
   SetCapture();
   m_Rect.right = m_Rect.left = point.x;
   m_Rect.bottom = m_Rect.top = point.y;
   Invalidate();
   CStatic::OnLButtonDown(nFlags, point);

}

------------------------------------------------------------------------------------------------------

CPictureBox.cpp -- These dont get the control when events are fired!

----------------------------------------------------------------------------------------------------
void CPictureBox::OnMouseMove(UINT nFlags, CPoint point)
{
   if (m_Tracking)
   {
      m_Rect.right = point.x;
      m_Rect.bottom = point.y;
      Invalidate();
   }

   CStatic::OnMouseMove(nFlags, point);
}

----------------------------
Main Dialog.cpp--
-----------------
BEGIN_MESSAGE_MAP(CmfcThsProj1Dlg, CDialog)
    ON_WM_SYSCOMMAND()
    ON_WM_PAINT()
    ON_WM_QUERYDRAGICON()
    //}}AFX_MSG_MAP
    ON_BN_CLICKED(IDC_BTN_BROWSE, OnBnClickedBtnBrowse)
    ON_WM_MOUSEMOVE()
    ON_STN_CLICKED(IDC_STATIC_PICBOX, OnStnClickedStaticPicbox)
END_MESSAGE_MAP()

void CmfcThsProj1Dlg::OnStnClickedStaticPicbox()
{
    // TODO: Add your control notification handler code here
    MessageBox("hello world");
    //CPictureBox::OnLButtonUp
    //m_PictureBox.Invalidate();
}

----------------------------------------------------------

-Thanks