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/LabelProvider.java
* <code>ILabelProvider</code> method returns <code>null</code>. Subclasses may 
 * override.
 */
public Image getImage(Object element) {
	return null;
}
/**
 * The <code>LabelProvider</code> implementation of this 
 * <code>ILabelProvider</code> method returns the element's <code>toString</code>
 * string. Subclasses may override.
 */
public String getText(Object element) {
	return element == null ? "" : element.toString();
}
/**
 * The <code>LabelProvider</code> implementation of this 
 * <code>IBaseLabelProvider</code> method returns <code>true</code>. Subclasses may 
 * override.
 */
public boolean isLabelProperty(Object element, String property) {
	return true;
}
/* (non-Javadoc)
 * Method declared on IBaseLabelProvider.
 */
public void removeListener(ILabelProviderListener listener) {
	listeners.remove(listener);
}
}