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/CheckboxTableViewer.java
* @param style style bits
 * @return a new table control
 */
protected static Table createTable(Composite parent, int style) {
	Table table = new Table(parent, SWT.CHECK | style);
	
	
	
	
	new TableColumn(table, SWT.NONE);
	TableLayout layout = new TableLayout();
	layout.addColumnData(new ColumnWeightData(100));
	table.setLayout(layout);
	
	return table;
}
/**
 * Notifies any check state listeners that a check state changed  has been received.
 * Only listeners registered at the time this method is called are notified.
 *
 * @param event a check state changed event
 *
 * @see ICheckStateListener#checkStateChanged
 */
private void fireCheckStateChanged(final CheckStateChangedEvent event) {
	Object[] array = checkStateListeners.getListeners();
	for (int i = 0; i < array.length; i ++) {
		final ICheckStateListener l = (ICheckStateListener)array[i];
		Platform.run(new SafeRunnable() {
			public void run() {