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
return result;
		String wsstr= Messages.format(PackagesMessages.PackageExplorer_toolTip, new String[] { fWorkingSetName }); 
		if (result.length() == 0)
			return wsstr;
		return Messages.format(PackagesMessages.PackageExplorer_toolTip2, new String[] { result, fWorkingSetName }); 
	}
	
	public String getTitleToolTip() {
		if (fViewer == null)
			return super.getTitleToolTip();
		return getToolTipText(fViewer.getInput());
	}
	
	/**
	 * @see IWorkbenchPart#setFocus()
	 */
	public void setFocus() {
		fViewer.getTree().setFocus();
	}
	/**
	 * Returns the current selection.
	 */
	private ISelection getSelection() {
		return fViewer.getSelection();
	}
	  
	
	
	/**
	 * Called when the context menu is about to open. Override