Bug 81877 Package explorer forgets active working set [package explorer]
3.1 M4 1. open pkg explorer. 2. select a working set, pkg explorer updates and filters out projects. 3. close pkg explorer. 4. open package explorer again and the working set is no longer applied. This used to work.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/packageview/PackageExplorerPart.java
Widget item= (Widget)iter.next();
					super.internalRefresh(item, element, true, updateLabels);				
				}
			}
		}
		protected void internalUpdate(Widget item, Object element, String[] properties) {
			List l= (List)fAdditionalMappings.get(element);
			if (l == null) {
				super.internalUpdate(item, element, properties);
			} else {
				List stable= new ArrayList(l);
				super.internalUpdate(item, element, properties);
				for (Iterator iter= stable.iterator(); iter.hasNext();) {
					Widget additionalItem= (Widget)iter.next();
					super.internalUpdate(additionalItem, element, properties);
				}
			}
		}
		public ISelection getSelection() {
			IContentProvider cp= getContentProvider();
			if (!(cp instanceof IMultiElementTreeContentProvider)) {
				return super.getSelection();
			}
			Control control = getControl();
			if (control == null || control.isDisposed()) {
				return StructuredSelection.EMPTY;
			}
			Tree tree= getTree();
			TreeItem[] selection= tree.getSelection();
			List result= new ArrayList(selection.length);