Bug 46669 [WorkingSets] "Select/Deselect All" button for working set creation wizard.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/ide/dialogs/ResourceWorkingSetPage.java
IWorkingSetPage {
    private final static int SIZING_SELECTION_WIDGET_WIDTH = 50;
    private final static int SIZING_SELECTION_WIDGET_HEIGHT = 200;
    private Text text;
    private CheckboxTreeViewer tree;
    private IWorkingSet workingSet;
    private boolean firstCheck = false; 
    /**
     * Creates a new instance of the receiver.
     */
    public ResourceWorkingSetPage() {
        super(
                "resourceWorkingSetPage",  
                IDEWorkbenchMessages.ResourceWorkingSetPage_title,
                IDEInternalWorkbenchImages
                        .getImageDescriptor(IDEInternalWorkbenchImages.IMG_WIZBAN_RESOURCEWORKINGSET_WIZ));
        setDescription(IDEWorkbenchMessages.ResourceWorkingSetPage_description);
    }
    /**
     * Adds working set elements contained in the given container to the list
     * of checked resources.
     * 
     * @param collectedResources list of collected resources
     * @param container container to collect working set elements for
     */
    private void addWorkingSetElements(List collectedResources,
            IContainer container) {
        IAdaptable[] elements = workingSet.getElements();
        IPath containerPath = container.getFullPath();