CoC Access Violation: Click PDA stats, then close PDA

[TIHan]

Describe the bug
This was tested with CoC 1.4.22.
Player opens the PDA, clicks "Statistics", then closes PDA. Crashes to desktop.

To Reproduce
Steps to reproduce the behavior:

1. Open the PDA
2. Click "Statistics"
3. Close PDA
4. Crashes to desktop for access violation

Expected behavior
Not crash

AV occurs here:

    for (auto it = m_ChildWndList.begin(); m_ChildWndList.end() != it; ++it)
    {
        if (!(*it)->IsShown()) // <-- AV here
            continue;
        (*it)->Update();
    }

I believe CUIRankingsCoC allowed this issue to be exposed considering CoP wouldn't use this. Its Update method does call into LUA:

void CUIRankingsCoC::Update()
{
    //if (ParentHasMe())
    //    return;

    luabind::functor<bool> functorCanShow;
    if (GEnv.ScriptEngine->functor("pda.coc_rankings_can_show", functorCanShow))
    {
        if (functorCanShow(m_index))
        {
            if (!ParentHasMe())
            {
                luabind::functor<pcstr> functorSetName;
                if (GEnv.ScriptEngine->functor("pda.coc_rankings_set_name", functorSetName))
                    SetName(functorSetName(m_index));

I'm not an expert in this codebase, but one possible fix could be changing:

void CUIPdaWnd::UpdateRankingWnd()
{
    if (pUIRankingWnd)
        pUIRankingWnd->Update();
}

to

void CUIPdaWnd::UpdateRankingWnd()
{
    if (m_pActiveDialog == pUIRankingWnd && pUIRankingWnd)
        pUIRankingWnd->Update();
}

It appears to fix the issue, and the rankings still display.

Another thing to note here is that this method:

void CUIRankingWnd::Update()
{
    inherited::Update();
    if (Device.dwTimeGlobal - m_previous_time > m_delay)
    {
        m_previous_time = Device.dwTimeGlobal;
        update_info();
    }
}

Used to not call inherited::Update();:

void CUIRankingWnd::Update()
{
    if (Device.dwTimeGlobal - m_previous_time > m_delay)
    {
        m_previous_time = Device.dwTimeGlobal;
        update_info();
    }
}

This also fixes the issue. Anomaly xray also does the same, but I understand why it was added in OpenXRay to prevent the scrollbar from freezing.