Bug 190061 [Metadata] Update @since tags for new API
Patch to follow
bundles/org.eclipse.jface.databinding/src/org/eclipse/jface/internal/databinding/provisional/viewers/UnorderedTreeContentProvider.java
} finally {
            avoidViewerUpdates--;
        }
    }
    
    private void removeIfUnused(TreeNode toRemove) {
        
        Object element = toRemove.getElement();
        if (toRemove.getParent() == null) {
            mapElementToTreeNode.remove(element);
            elements.doFireDiff(Collections.EMPTY_SET, Collections.singleton(element));
            toRemove.dispose();
        }
    }
    private void setViewer(Viewer viewer) {
        if (viewer != null && !(viewer instanceof TreeViewer)) {
            throw new IllegalArgumentException("This content provider can only be used with TreeViewers"); 
        }
        TreeViewer newTreeViewer = (TreeViewer) viewer;
        
        if (newTreeViewer != treeViewer) {
            if (treeViewer != null) {
                treeViewer.removeTreeListener(expandListener);
            }
            
            this.treeViewer = newTreeViewer;
            if (newTreeViewer != null) {
                newTreeViewer.addTreeListener(expandListener);
            }
        }