OnEraseBkgd

I am going totally mad here.

I have a class CStrEdit derived from CEdit.

I have an instance as a member of my CView derived class, which I use to
edit text "in place" on the CView. It should be effectively transparent.
So I arrange for it to contain the same chunk of text which is in the CView,
and this week's method is to give the CStrEdit class a member

CBitmap *ee-pBmpBgd;

In OnShowWindow(), this bitmap is created as a copy of the rectangle of the
CView over which my CStrEdit sits. The idea is that OnEraseBkgnd should
blit the bitmap on the CStrEdit making it look just like the CView
underneath! As a debugging device I have also given it an HBRUSH member
in a nice distinctive pink colour and return it in response to WM_CTLCOLOR.

A I step through OnEraseBkgnd (appended), it steps through the call to the
base class and the bitmap drawing code and nothing happens on my view
window. Then at some time after OnEraseBkgnd has happened, the pink
rectangle appears - but no bitmap! [The bitmap is correct - I have drawn it
in a debugging dialogue in passing in order to check!]

I have been changing the code a lot trying to work this out. Earlier I was
using a slightly different method and it worked, but it failed as soon as I
started using CommonControls6. I feel it should be obvious what is going
on but ta the moment I'm baffled. Any ideas?

Dave
--
David Webber
Author of 'Mozart the Music Processor'
http://www.mozart.co.uk
For discussion/support see
http://www.mozart.co.uk/mzusers/mailinglist.htm

BOOL CStrEdit::OnEraseBkgnd( CDC* pDC )
{
 BOOL bResult = TRUE;

 if( ee_pBmpBkgd && ee_pBmpBkgd->GetSafeHandle() )
 {
     // Call the base class which should draw
     // with the brush....

      bResult = CEdit::OnEraseBkgnd( pDC );

      // There's a bitmap, so use that on top:

      CRect Rect;
      GetClientRect(&Rect);

      int cx = Rect.Width();
      in t cy = Rect.Height();
      CDC MemDC;
      MemDC.CreateCompatibleDC(pDC);
      CBitmap *pOldBmp = MemDC.SelectObject( ee_pBmpBkgd );
      pDC->BitBlt( 0, 0, cx, cy, &MemDC, 0, 0, SRCCOPY );
      MemDC.SelectObject( pOldBmp );

      bResult = TRUE;
 }
 else
 {
      bResult = CEdit::OnEraseBkgnd( pDC );
 }

 return bResult;
}