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/StructuredViewer.java
protected Item getItem(int x, int y) {
	return null;
}
/**
 * Returns the children of the given parent without sorting and 
 * filtering them.  
 * The resulting array must not be modified,
 * as it may come directly from the model's internal state.
 * <p>
 * Returns an empty array if the given parent is <code>null</code>.
 * </p>
 *
 * @param parent the parent element
 * @return the child elements
 */
protected Object[] getRawChildren(Object parent) {
	Object[] result = null;
	if (parent != null) {
		result = ((IStructuredContentProvider) getContentProvider()).getElements(parent);
		Assert.isNotNull(result);
	}
	return (result != null) ? result : new Object[0];
}
/**
 * Returns the root element.
 * <p>
 * The default implementation of this framework method forwards to
 * <code>getInput</code>.
 * Override if the root element is different from the viewer's input
 * element.