Upon initial opening of a QDialog containing QTabHdr or QTabWidget with QListWidget, sometimes the active tab text is garbles as per one of the attached screenshots. ( I have since discovered QTableWidget suffers the same fate too )

In the same time, if you click on an item in the List, all the items below the selected item become grayed out.

The attached project exhibits the same behavior.

Possibly QFusionStyle doesn't paint properly???

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I have now tried the following

QString style = "Windows";
QApplication::setStyle(QStyleFactory::create(style));

This mitigates the issues. So it would appear that the issue happens when using the QFusionStyle