When using a QComboBox with custom delegates that include checkboxes in Qt 6.7.x or later, the items and checkboxes inside the combo box overlap, leading to a broken UI layout. The issue occurs specifically with the new windows11 style introduced in Qt 6.7. Downgrading to Qt 6.6.3 resolves the issue, suggesting that the problem may be related to the style changes. The same behavior might also occur with other item views (e.g., QListView) using similar delegate implementations.