Eu implementei um CScrollBar em um Cwnd, mas depois de rolar os controles na janela desaparecem. Ouvi dizer que poderia usar o DeferWindowPos de alguma forma, mas não sei como fazer isso. Alguma ideia?

CPanel::CPanel()
{
    CreateEx(WS_EX_CONTROLPARENT, _T("Static"), NULL, WS_CHILD | WS_TABSTOP | WS_BORDER, m_clRect, pwndParent, IDC_PANEL_FORM);
    ScrollBarInit();    
}

Criando barra de rolagem

void CPanel::ScrollBarInit()
{

    //Before this i calculate size of scrollbar and size of scrollarea
    m_pclScrollBar = new CScrollBar();
    m_pclScrollBar->Create(WS_CHILD | WS_VISIBLE | SBS_VERT | SBS_RIGHTALIGN, clRectScrollbar, this, IDC_SCROLLBAR_FORM);
    m_pclScrollBar->SetScrollRange(VSCROLL_RANGE_MIN, VSCROLL_RANGE_MAX);
    //After this I add scrollbar info

}

Manipular mensagem

void CPanel::OnVScroll(UINT iSBCode, UINT iPos, CScrollBar* pclScrollBar)
    {
        switch(pclScrollBar->GetDlgCtrlID())
        {
            case IDC_SCROLLBAR_FORM:
                ScrollBarScroll(iSBCode, iPos, pclScrollBar);
                break;
        }
    }

Rolagem

void CPanel::ScrollBarScroll(UINT iSBCode, UINT iPos, CScrollBar *pclScrollBar)
    {
        int     iScrollPositionPrevious;
        int     iScrollPosition;
        int     iScrollPositionOriginal;

        iScrollPositionOriginal = m_pclScrollBar->GetScrollPos();
        iScrollPosition = iScrollPositionOriginal;

        if(m_pclScrollBar != NULL)
        {
            SCROLLINFO info = {sizeof( SCROLLINFO ), SIF_ALL};
            pclScrollBar->GetScrollInfo(&info, SB_CTL);

            pclScrollBar->GetScrollRange(&info.nMin, &info.nMax);
            info.nPos = pclScrollBar->GetScrollPos();

            iScrollPositionPrevious = info.nPos;

            switch(iSBCode)
            {
                case SB_TOP:            // Scroll to top
                    iScrollPosition = VSCROLL_RANGE_MIN;
                    break;

                case SB_BOTTOM:         // Scroll to bottom
                    iScrollPosition = VSCROLL_RANGE_MAX;
                    break;

                case SB_ENDSCROLL:      // End scroll
                    break;

                case SB_LINEUP:         // Scroll one line up
                    if(iScrollPosition - VSCROLL_LINE >= VSCROLL_RANGE_MIN)
                        iScrollPosition -= VSCROLL_LINE;
                    else
                        iScrollPosition = VSCROLL_RANGE_MIN;
                    break;

                case SB_LINEDOWN:       // Scroll one line down
                    if(iScrollPosition + VSCROLL_LINE <= VSCROLL_RANGE_MAX)
                        iScrollPosition += VSCROLL_LINE;
                    else
                        iScrollPosition = VSCROLL_RANGE_MAX;
                    break;

                case SB_PAGEUP:         // Scroll one page up
                {
                    // Get the page size
                    SCROLLINFO   scrollInfo;
                    m_pclScrollBar->GetScrollInfo(&scrollInfo, SIF_ALL);

                    if(iScrollPosition > VSCROLL_RANGE_MIN)
                        iScrollPosition = max(VSCROLL_RANGE_MIN, iScrollPosition - VSCROLL_PAGE);
                    break;
                }

                case SB_PAGEDOWN:       // Scroll one page down
                {
                    // Get the page size
                    SCROLLINFO   scrollInfo;
                    m_pclScrollBar->GetScrollInfo(&scrollInfo, SIF_ALL);

                    if(iScrollPosition < VSCROLL_RANGE_MAX)
                        iScrollPosition = min(VSCROLL_RANGE_MAX, iScrollPosition + VSCROLL_PAGE);
                    break;
                }

                case SB_THUMBPOSITION:  // Scroll to the absolute position. The current position is provided in nPos
                case SB_THUMBTRACK:     // Drag scroll box to specified position. The current position is provided in nPos
                    iScrollPosition = iPos;
                    break;

                default:
                    break;
            }

            if(iScrollPositionOriginal != iScrollPosition)
            {
               m_pclScrollBar->SetScrollPos(iScrollPosition);

               CRect clientArea;
               GetClientRect(clientArea);

               CRect scrollbarArea;
               m_pclScrollBar->GetWindowRect(scrollbarArea);

               CRect scrollArea(clientArea);
               scrollArea.DeflateRect(0, 0, scrollbarArea.Width(), 0);
               ScrollWindowEx(0, iScrollPositionOriginal - iScrollPosition, scrollArea, NULL,
                       NULL, NULL, SW_SCROLLCHILDREN | SW_INVALIDATE | SW_ERASE);
            }
        }
    }