$20 to solve this webview transparency / drawing bug

[wysota]

That's not good. Try:

setWindowFlags(Qt::Popup);

setWindowFlags(Qt::Popup);

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or

setWindowFlags(Qt::ToolTip);

setWindowFlags(Qt::ToolTip);

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Also try simplifying your code as much as possible. First of all see how everything behaves when you substitute QWebView with some other widget (say... QLabel).