Bug 49121 Link with Editor does not reveal selection if unchanged
build I20031218 - open a CU - in package explorer, toggle Link with Editor on - it shows the selection - scroll the selection out of view - toggle Link with Editor off then back on - the selection is not shown
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/packageview/PackageExplorerPart.java
public PackageExplorerProblemTreeViewer(Composite parent, int style) {
			super(parent, style);
			fPendingGetChildren= Collections.synchronizedList(new ArrayList());
		}
		public void add(Object parentElement, Object[] childElements) {
			if (fPendingGetChildren.contains(parentElement)) 
				return;
			super.add(parentElement, childElements);
		}
				
		protected Object[] getRawChildren(Object parent) {
			try {
				fPendingGetChildren.add(parent);
				return super.getRawChildren(parent);				
			} finally {
				fPendingGetChildren.remove(parent);
			}
		}
		
		/*
		 * @see org.eclipse.jface.viewers.StructuredViewer#filter(java.lang.Object)
		 */
		protected Object[] getFilteredChildren(Object parent) {
			List list = new ArrayList();
			ViewerFilter[] filters = fViewer.getFilters();
			Object[] children = ((ITreeContentProvider) fViewer.getContentProvider()).getChildren(parent);
			for (int i = 0; i < children.length; i++) {
				Object object = children[i];
				if (!isEssential(object)) {