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
/* (non-Javadoc)
 * Method declared on ICheckable.
 */
public void addCheckStateListener(ICheckStateListener listener) {
	checkStateListeners.add(listener);
}
/**
 * Applies the checked and grayed states of the given widget and its
 * descendents.
 *
 * @param checked a set of elements (element type: <code>Object</code>) 
 * @param grayed a set of elements (element type: <code>Object</code>) 
 * @param widget the widget
 */
private void applyState(Set checked, Set grayed, Widget widget) {
	Item[] items = getChildren(widget);
	for (int i = 0; i < items.length; i++) {
		Item item = items[i];
		if (item instanceof TreeItem) {
			Object data = item.getData();
			if (data != null) {
				TreeItem ti = (TreeItem) item;
				ti.setChecked(checked.contains(data));
				ti.setGrayed(grayed.contains(data));
			}
		}
		applyState(checked, grayed, item);
	}
}
/**