I had this exact problem, and it was a tough to find but simple fix. When I changed my view from being derived from CView to CScrollView, I missed changing the reference in the message map... In my case
BEGIN_MESSAGE_MAP(CLayoutView, CView)
should have been:
BEGIN_MESSAGE_MAP(CLayoutView, CScrollView)
Once I found and corrected this error, the view started scrolling as expected.
