Today I reimplemented the tree view based on a DomModel taken from the SimpleDomModel example, and hooked that up to a QTreeView, replacing the QTreeWidget. This works great. The next phase is to filter that model into QListView, which I'm assured by someone on one of the QT forums can be done by subclassing QSortFilterProxyModel, and implementing filterRows and filterColumns. This I've now done, but the results are not encouraging: nothing shows up in my list. At this point, I'm not sure whether this is because the filter method code is flawed, so it's never accepting a row, or because when a row is rejected, its children are never tested, which means that you can't get down as far as a list of elements which have @xml:ids; or even because child rows are never tested at all, so only the top level nodes get as far as the filter. At the moment, I'm tending towards the last option, because even when I make my function return true in all cases, only the top level nodes show up.

I'm sure I'm on the right track here, but it's going to take some more work...