Bug 15844 [Exception Handling] SelectionChange events and NPE
Build 20020508 Due to new global actions there are now more objects listening to selection changes send out by a JFace viewer. We now had the case that one of the listener generated a NPE. As a result all listeners registered after that one didn't receive the selection change event. StructuredViewers should be more fault tolorant to exceptions when informing listeners.
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/CheckboxTreeViewer.java
* @param state <code>true</code> if the item should be checked,
 *  and <code>false</code> if it should be unchecked
 */
private void setCheckedChildren(Item item, boolean state) {
	createChildren(item);
	Item[] items = getChildren(item);
	if (items != null) {
		for (int i = 0; i < items.length; i++) {
			Item it = items[i];
			if (it.getData() != null && (it instanceof TreeItem)) {
				TreeItem treeItem = (TreeItem) it;
				treeItem.setChecked(state);
				setCheckedChildren(treeItem, state);
			}
		}
	}
}
/**
 * Sets which elements are checked in this viewer's tree.
 * The given list contains the elements that are to be checked;
 * all other elements are to be unchecked.
 * <p>
 * This method is typically used when restoring the interesting
 * state of a viewer captured by an earlier call to <code>getCheckedElements</code>.
 * </p>
 *
 * @param elements the array of checked elements
 * @see #getCheckedElements
 */
public void setCheckedElements(Object[] elements) {