[Bug 52327] Wrong WM_CONTEXTMENU message default processing

[WineHQ Bugzilla]

https://bugs.winehq.org/show_bug.cgi?id=52327

--- Comment #4 from YAL  ---
Software is nanoCAD CAD solution and I'm responsible for adapting it under
*nix. 
I can write test - VS studio project? Or just exe file?

I've sent to screenshots illustrated this bug - first under WINE, second under
Windows. Difference in pWnd argument which in first case pointed to toplevel
child (CMFCTabCtrl) and in second (right case) to nearest (CMDICliaentAreaWnd).

void CMDIFrameWndEx::OnContextMenu(CWnd* pWnd, CPoint point)
{
    if (m_wndClientArea.GetMDITabs().GetSafeHwnd() == NULL)
    {
        Default();
        return;
    }

if (CMFCPopupMenu::GetActiveMenu() != NULL)
    {
        return;
    }

if ((GetAsyncKeyState(::GetSystemMetrics(SM_SWAPBUTTON) ? VK_RBUTTON :
VK_LBUTTON) & 0x8000) != 0) // "Left" mouse button is pressed
    {
        return;
    }

if (pWnd->GetSafeHwnd() == m_wndClientArea.GetSafeHwnd()) <=== This case
not working under WINE - wrong child
    {
        CWnd* pWndCur = WindowFromPoint(point);