Point taken; thanks.

But I succeeded in getting the functionality I needed with just +5 lines of code, using a function provided by QTreeWidget itself, not some hack:

Qt Code: 
  1. void QTreeWidget::openPersistentEditor(QTreeWidgetItem*item,int column)
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I capture the user's editing changes with the slot

Qt Code: 
  1. void QTreeWidget::itemChanged(QTreeWidgetItem * item, int column)
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So I feel I was not trying to do too much with the convenience class. I was just slow to find the solution. This feature of my app is a small, simple sidelight, not a central, expandible effort, so I'm done and it's stable. Movin' on ...

But thanks for the advice.