Bug 93400 LTK UI should provide official API for structural content in the preview page
org.eclipse.ltk.ui.refactoring/src/org/eclipse/ltk/internal/ui/refactoring/ChangeElementTreeViewer.java
}
	}
	
	protected void doUpdateItem(Item item, Object element) {
		super.doUpdateItem(item, element);
		if (fDeferredTreeItemUpdates == null) {
			applyCheckedState((TreeItem)item, (ChangeElement)element);
		} else {
			fDeferredTreeItemUpdates.add(item);
		}
	}
	
	private void processDeferredTreeItemUpdates() {
		for (Iterator iter= fDeferredTreeItemUpdates.iterator(); iter.hasNext();) {
			TreeItem item= (TreeItem)iter.next();
			applyCheckedState(item, (ChangeElement)item.getData());
		}
	}
	
	private void applyCheckedState(TreeItem item, ChangeElement ce) {
		int state= ce.getActive();
		boolean checked= state == ChangeElement.INACTIVE ? false : true;
		item.setChecked(checked);
		boolean grayed= state == ChangeElement.PARTLY_ACTIVE ? true : false;
		item.setGrayed(grayed);
	}
	
	protected void revealNext() {
		revealElement(true);
	}