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/AbstractTreeViewer.java
}
	}
	/**
	 * Refreshes the tree starting at the given widget.
	 * 
	 * @param widget
	 *           the widget
	 * @param element
	 *           the element
	 * @param doStruct
	 *           <code>true</code> if structural changes are to be picked up,
	 *           and <code>false</code> if only label provider changes are of
	 *           interest
	 * @param updateLabels
	 *           <code>true</code> to update labels for existing elements,
	 *           <code>false</code> to only update labels as needed, assuming
	 *           that labels for existing elements are unchanged.
	 */
	private void internalRefresh(
		Widget widget,
		Object element,
		boolean doStruct,
		boolean updateLabels) {
		if (widget instanceof Item) {
			if (doStruct) {
				updatePlus((Item) widget, element);
			}
			if (updateLabels || !equals(element, widget.getData())) {
				doUpdateItem(widget, element, true);
			} else {