Bug 18486 Need documentation for startup extension point.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/browsing/JavaBrowsingContentProvider.java
if (ctrl != null && !ctrl.isDisposed())
					fViewer.refresh(root);
			}
		});
	}
	private void postAdd(final Object parent, final Object element) {
		postAdd(parent, new Object[] {element});
	}
		
	private void postAdd(final Object parent, final Object[] elements) {
		if (elements.length <= 0)
			return;
		
		postRunnable(new Runnable() {
			public void run() {
				Control ctrl= fViewer.getControl();
				if (ctrl != null && !ctrl.isDisposed()) {
					ctrl.setRedraw(false);
					if (fViewer instanceof AbstractTreeViewer) {
						if (fViewer.testFindItem(parent) == null) {
							Object root= ((AbstractTreeViewer)fViewer).getInput();
							if (root != null)
								((AbstractTreeViewer)fViewer).add(root, elements);
						}
						else
							((AbstractTreeViewer)fViewer).add(parent, elements);
					}
					else if (fViewer instanceof ListViewer)
						((ListViewer)fViewer).add(elements);
					else if (fViewer instanceof TableViewer)