how to fix the whole white widget what is in fact not ?

[nicker player]

Ive made a desktop app,and it worked fine in some windows platform.but one was shown nothing but only the whole white widget,and the debugger dosent give me anything useful.so what part of the code caused this problem.

QtWebEngine::initialize();
QApplication::setAttribute(Qt::AA_UseOpenGLES);
QString t_style = "windowsxp";
    QStringList keyList = QStyleFactory::keys();
    for(int i = 0; i < keyList.length(); i++)
    {
        t_style = keyList.at(i);
        if(t_style.contains("vista") || t_style.contains("Vista")){
            t_style = "windowsvista";
        }
    }
QApplication::setStyle(QStyleFactory::create(t_style));
QApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
QApplication::setHighDpiScaleFactorRoundingPolicy(Qt::HighDpiScaleFactorRoundingPolicy::PassThrough);
        QGuiApplication::setAttribute(Qt::AA_UseHighDpiPixmaps);

[JonB]

I don't know. But how do we or you know whether you are using style windowsxp or windowsvista? Simple common sense: Start by removing the if and testing once with windowsxp or windowsvista unconditionally. Does that make any difference? If yes then it's something to do with style, if not then the style is not at issue.