I maybe found a bug in TreeView, when using items with custom components, with option rootItemVisible = false.
In my application, the bottom-most item was clipped too early. The following lines in TreeViewContentComponent::updateComponents() fixed the problem:
TreeViewItem* item = owner->rootItem; + if (item && !owner->rootItemVisible) + yAdjust = item->itemHeight; int y = -yAdjust;
By the way, the variable yAdjust was always equal to 0 and thus useless.