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
* to add your own context dependent menu contributions.
	 */
	public void menuAboutToShow(IMenuManager menu) {
		JavaPlugin.createStandardGroups(menu);
		
		fActionSet.setContext(new ActionContext(getSelection()));
		fActionSet.fillContextMenu(menu);
		fActionSet.setContext(null);
	}
	private void makeActions() {
		final PerformanceStats stats= PerformanceStats.getStats(PERF_MAKE_ACTIONS, this);
		stats.startRun();
		fActionSet= new PackageExplorerActionGroup(this);
		if (fWorkingSetModel != null)
			fActionSet.getWorkingSetActionGroup().setWorkingSetModel(fWorkingSetModel);
		stats.endRun();
	}
	
	
	
	private void initDragAndDrop() {
		initDrag();
		initDrop();
	}
	private void initDrag() {
		int ops= DND.DROP_COPY | DND.DROP_MOVE | DND.DROP_LINK;
		Transfer[] transfers= new Transfer[] {
			LocalSelectionTransfer.getInstance(), 
			ResourceTransfer.getInstance(),
			FileTransfer.getInstance()};