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
elements.add(element);
			}
			fViewer.setExpandedElements(elements.toArray());
		}
	}
	
	/**
	 * Create the KeyListener for doing the refresh on the viewer.
	 */
	private void initKeyListener() {
		fViewer.getControl().addKeyListener(new KeyAdapter() {
			public void keyReleased(KeyEvent event) {
				fActionSet.handleKeyEvent(event);
			}
		});
	}
	/**
	 * An editor has been activated.  Set the selection in this Packages Viewer
	 * to be the editor's input, if linking is enabled.
	 */
	void editorActivated(IEditorPart editor) {
		if (!isLinkingEnabled())  
			return;
		Object input= getElementOfInput(editor.getEditorInput());
		if (input == null) 
			return;
		if (!inputIsSelected(editor.getEditorInput()))
			showInput(input);
		else
			getTreeViewer().getTree().showSelection();