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/AbstractTreeViewer.java
return null;
	Widget w= findItem(element);
	if (w == null) {	
		if (element.equals(getRoot()))	
			return null;
		
		Object parent= ((ITreeContentProvider) getContentProvider()).getParent(element);
		if (parent != null) {
			Widget pw= internalExpand(parent, expand);
			if (pw != null) {
				
				createChildren(pw);
				
				if (pw instanceof Item) {
					Item item= (Item)pw;
					if (expand)
						setExpanded(item, true);
					w= internalFindChild(item, element);
				}
			}
		}
	}
	return w;
}
/**
 * Recursively expands the subtree rooted at the given widget to the
 * given level.
 * <p>
 * </p>
 * Note that the default implementation of this method does not call