Bug 67851 SelectionListenerWithASTManager should synchronized access to listener list
RC2, for post 3.0: SelectionListenerWithASTManager.PartListenerGroup should protect the access to the ListenerList from the job.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/viewsupport/SelectionListenerWithASTManager.java
private static SelectionListenerWithASTManager fgDefault;
	
	/**
	 * @return Returns the default manager instance.
	 */
	public static SelectionListenerWithASTManager getDefault() {
		if (fgDefault == null) {
			fgDefault= new SelectionListenerWithASTManager();
		}
		return fgDefault;
	}
	
	
	private final static class PartListenerGroup {
		private ITextEditor fPart;
		private ISelectionChangedListener fSelectionListener, fPostSelectionListener;
		private Job fCurrentJob;
		private ListenerList fAstListeners;
		
		public PartListenerGroup(ITextEditor part) {
			fPart= part;
			fCurrentJob= null;
			fAstListeners= new ListenerList();
			
			fSelectionListener= new ISelectionChangedListener() {
				public void selectionChanged(SelectionChangedEvent event) {
					ISelection selection= event.getSelection();