QTableWidget sizeHint Not Called

I have a QTableWidget that contains cells of popup menus, set in the table using QTableWidget::setCellWidget. The popup menus are a subclass of QToolButton with a menu set on the button. The subclass overrides QToolButton's sizeHint and its size policy is preferred/preferred (I've also tried fixed), but nothing I do results in sizeHint being called, including calling QTableWidget::resizeRowsToContents ans resizeColumnsToContents. Is there something else I have to do to cause rows and columns to resize to the size of these popup menus?