Bug 32254 [Viewers] AbstractTreeViewer uses HashSet to remember expansion state
I20030216 The custom hash table should be used instead. Otherwise expansion state may be lost due to a different equals implementation of the element and the IElementComparer.
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/TreeViewer.java
if(items.size() != current.length)
		return false;
	
	Set values = new HashSet();
	Iterator itemsIterator = items.iterator();
	
	
	while(itemsIterator.hasNext()){
		values.add(((Item) itemsIterator.next()).getData());
	}
	
	
	
	for (int i = 0; i < current.length; i++) {
		if(values.contains(current[i].getData()))
			continue;
		return false;
	}
	
	return true;
}
/* (non-Javadoc)
 * Method declared in AbstractTreeViewer.
 */
protected void showItem(Item item) {
	getTree().showItem((TreeItem)item);
}
}