The ui.wndTree is an instance of Tree. I have created a splitter layout in the Designer, put a QTreeWidget and a QTextEdit into it and promoted the QTreeWidget to Tree and QTextEdit to Text. The Tree class contains a TreeHeader pointer to QHeaderView, which should be shown in some views and not shown in others. The views are:

case 1: side by side, no header
case 2: top and bottom, header
case 3: only tree, header
case 4: only text, no header

The views are cycled by a view selector.