Bug 81426 Package Explorer shows nothing after drill into working set, then show projects
I200412160800 - switch Package Explorer to working sets - context menu > Go Into a working set - Show > Projects -> view is empty -> view toolbar button 'Up to Working Sets' does not do anything
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/packageview/PackageExplorerPart.java
public boolean show(ShowInContext context) {
		Object input= context.getInput();
		if (input instanceof IEditorInput) {
			Object elementOfInput= getElementOfInput((IEditorInput)context.getInput());
			if (elementOfInput == null) 
				return false; 
			return tryToReveal(elementOfInput);
		}
		ISelection selection= context.getSelection();
		if (selection != null) {
			 
			if (selection instanceof IStructuredSelection) {
				IStructuredSelection structuredSelection= ((IStructuredSelection) selection);
				if (structuredSelection.size() == 1)  
					return tryToReveal(structuredSelection.getFirstElement());
			}
			selectReveal(selection);
			return true;
		}
		return false;
	}
	/**
	 * Returns the <code>IShowInSource</code> for this view.
	 */
	protected IShowInSource getShowInSource() {
		return new IShowInSource() {
			public ShowInContext getShowInContext() {
				return new ShowInContext(
					getViewer().getInput(),
					getViewer().getSelection());