问在wxWidgets中创建全局wxCriticalSection变量是不是很糟糕？

EN

BEGIN_EVENT_TABLE(MyFrame, wxFrame)
EVT_TREELIST_ITEM_EXPANDED(wxID_ANY, MyFrame::OnItemExpand)   
EVT_THREAD(ITEM_BROWSE_WORKER_EVENT,MyFrame::OnExpandThreadCompletion)
END_EVENT_TABLE()

//using below 2 variables to avoid crash when item expansion request is sent and user closes the frame.
 wxCriticalSection cs_forisFrameClosed;
 static bool isFrameClosed;

MyFrame::MyFrame()
{
   {
    wxCriticalSectionLocker lock(cs_forisFrameClosed);
    isFrameClosed = false;
   }
   //remaining code ...
}

MyFrame::~MyFrame()
{
   {
    wxCriticalSectionLocker lock(cs_forisFrameClosed);
    isFrameClosed = true;
   }
}

void MyFrame::OnItemExpand(wxTreeListEvent& event)
{
     MyThread *thread = new MyThread(this);
    if (thread->Create() != wxTHREAD_NO_ERROR)
    {
        PrintError(__FUNCTION__, "Can't create thread!");
    }
    thread->Run();
}

MyThread::MyThread(MyFrame *frame) : wxThread()
{
    m_frame = frame;
}

wxThread::ExitCode MyThread::Entry()
{
    string resp;
    GetResponseFromBackEnd(resp);
    {
        wxCriticalSectionLocker lock(cs_forisFrameClosed);
        if (!isFrameClosed)
        {
            wxThreadEvent event(wxEVT_THREAD, ITEM_BROWSE_WORKER_EVENT);
            event.SetString(resp);
            wxQueueEvent(m_frame, event.Clone());
        }
    }
}


void MyFrame::OnExpandThreadCompletion(wxThreadEvent &event)
{
    // this function is executed after every thread returns.
    // take response from event and update tree with children.      
}