Bug 164509 Breaking API change: ColumnViewer#getItemAt(Point)
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/AbstractTreeViewer.java
if (usingElementMap()) {
			disassociateChildren(item);
		}
	}
	/**
	 * Disassociates the children of the given SWT item from their corresponding
	 * elements.
	 * 
	 * @param item
	 *            the widget
	 */
	private void disassociateChildren(Item item) {
		Item[] items = getChildren(item);
		for (int i = 0; i < items.length; i++) {
			if (items[i].getData() != null) {
				disassociate(items[i]);
			}
		}
	}
	
	protected Widget doFindInputItem(Object element) {
		
		Object root = getRoot();
		if (root == null) {
			return null;
		}
		if (equals(root, element)) {
			return getControl();
		}
		return null;