Bug 159550 [Viewers] Deprecate TableTreeViewer
The underlying SWT-controls of TableTreeViewer (TableTree,TableTreeItem,TableTreeEditor) are deprecated and so should TableTreeViewer I think.
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/TableTreeViewer.java
/**
     * Internal table viewer implementation.
     */
    private TableEditorImpl tableViewerImpl;
    /**
     * This viewer's table tree control.
     */
    private TableTree tableTree;
    /**
     * This viewer's table tree editor.
     */
    private TableTreeEditor tableTreeEditor;
    /**
     * Private implementation class.
     */
    class TableTreeViewerImpl extends TableEditorImpl {