I've tested this Qt4 on Linux with several styles and it work with others but cleanlooks.
You can try yourself, for example
programname -style plastique
programname -style plastique
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Interestingly, if I set the list view as the combobox view
combo->setView(new QListView);
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I get checkable items, but clickingan item does not close the popup.
With Qt5 I get the behavior with all styles.
Perhaps something to search the bug database for.
Cheers,
_
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