QComboBox with AdjustToContents doesn't update size when proxy model is invalidated

I have a QComboBox on which I have called setSizeAdjustPolicy(QComboBox::AdjustToContents). The combo box's model is set to a QSortFilterProxyModel subclass.

When the combo box is first shown, the proxy model filters out all items. Later, conditions change and the proxy model no longer filters out all items. However the width of the combo box isn't properly updated.

To reproduce this, build the attached example and click the Update button. Note that the item in the combo box is elided. This is incorrect behavior.

To see the expected behavior, uncomment line 55 in the example and rebuild.