PRB: CBS_SIMPLE ComboBox Repainting Problem

RESOLUTION

Sample Code

   LRESULT CALLBACK NewComboProc(
         HWND hWnd,
         UINT uMessage,
         WPARAM uParam,
         LPARAM lParam)
   {
   HDC myDC;
   HPEN   hPen, hOldPen;
   HBRUSH hBrush;
   HBRUSH hOldBrush;
   COLORREF myColor=RGB(255,255,255); //It can be any color. Here
                                      //the area is painted white.

   HWND hEdit, hList;
   RECT comboRect, editRect, listRect;
   char   *wndClassName="Edit";

   if (uMessage == WM_PAINT)
     {
     CallWindowProc(lpfnOldComboProc, hWnd, uMessage, uParam,
                    lParam);
     myDC = GetDC(hWnd);
     hBrush = CreateSolidBrush(myColor);
     hPen   = CreatePen (PS_SOLID, 1, myColor);
     hOldBrush = SelectObject(myDC, hBrush) ;
     hOldPen   = SelectObject(myDC, hPen);

     //This code obtains the handle to the edit control of the
     //combobox.

     hEdit = GetWindow(hWnd, GW_CHILD);
     GetClassName (hEdit, wndClassName, 10);
     if (!lstrcmp (wndClassName, "Edit"))

       hList=GetWindow(hEdit, GW_HWNDNEXT);

     else
       {
       hList=hEdit;
       hEdit=GetWindow(hList, GW_HWNDNEXT);
       }

     //The dimensions of the Edit Control, ListBox control and
     //the Combobox are calculated and then used
     //as the base dimensions for the Rectangle() routine.

     GetClientRect (hWnd, &comboRect);
     GetClientRect (hEdit, &editRect);
     GetClientRect (hList, &listRect);
     Rectangle (myDC,
                comboRect.left,
                editRect.bottom,
                comboRect.right-listRect.right,
                comboRect.bottom);
     //Also paint the gap, if any exists, between the bottom
     //of the listbox and the bottom of the ComboBox rectangle.
     Rectangle (myDC,
                comboRect.right-listRect.right,
           editRect.bottom +
                listRect.bottom,
           comboRect.right,
           comboRect.bottom);

     DeleteObject(SelectObject(myDC, hOldBrush)) ;
     DeleteObject(SelectObject(myDC, hOldPen)) ;
     ReleaseDC(hWnd, myDC);
     return TRUE;
     }

   return CallWindowProc(lpfnOldComboProc, hWnd, uMessage, uParam,
    lParam);
   }