QComboBox custom item delegate returns immediately when clicked in Qt5

QComboBox closes immediately when clicked for editing. Examples/previous code work fine in Qt4.

Occurs in Color Editor Factory Example. Similarly, QSpinBox Delegate Example works fine with the QSpinBox, but exhibits the same closing behavior when the QSpinBox is changed to a QComboBox. The snippet at http://qt-project.org/wiki/Combo_Boxes_in_Item_Views works well to demonstrate the problem. Works in Qt4, broken in Qt5.

The QComboBox is created as an editor, and allows its value to be changed and set by using the arrow keys. Using openPersistentEditor on the view works as a temporary hack/workaround.