Bug 153993 [Viewers] Common Baseclass for Tree/TableEditorImpl
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/TreeViewer.java
public void setCellModifier(ICellModifier modifier) {
		treeViewerImpl.setCellModifier(modifier);
	}
	/**
	 * Sets the column properties of this tree viewer. The properties must
	 * correspond with the columns of the tree control. They are used to
	 * identify the column in a cell modifier.
	 * 
	 * @param columnProperties
	 *            the list of column properties
	 * @since 3.1
	 */
	public void setColumnProperties(String[] columnProperties) {
		treeViewerImpl.setColumnProperties(columnProperties);
	}
	/*
	 * (non-Javadoc) Method declared in AbstractTreeViewer.
	 */
	protected void setExpanded(Item node, boolean expand) {
		((TreeItem) node).setExpanded(expand);
		if (contentProviderIsLazy) {
			
			getControl().update();
		}
	}
	/*
	 * (non-Javadoc) Method declared in AbstractTreeViewer.
	 */
	protected void setSelection(List items) {
		Item[] current = getSelection(getTree());