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/CheckboxTreeViewer.java
}
}
/* (non-Javadoc)
 * Method declared on ICheckable.
 */
public boolean getChecked(Object element) {
	Widget widget = findItem(element);
	if (widget instanceof TreeItem)
		return ((TreeItem) widget).getChecked();
	return false;
}
/**
 * Returns a list of checked elements in this viewer's tree, 
 * including currently hidden ones that are marked as
 * checked but are under a collapsed ancestor.
 * <p>
 * This method is typically used when preserving the interesting
 * state of a viewer; <code>setCheckedElements</code> is used during the restore.
 * </p>
 *
 * @return the array of checked elements
 *
 * @see #setCheckedElements
 */
public Object[] getCheckedElements() {
	ArrayList v = new ArrayList();
	Control tree = getControl();
	internalCollectChecked(v, tree);
	return v.toArray();
}