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
* Returns the name entered in the working set name field.
     * 
     * @return the name entered in the working set name field.
     */
    private String getWorkingSetName() {
        return text.getText();
    }
    /**
     * Called when the checked state of a tree item changes.
     * 
     * @param event the checked state change event.
     */
    private void handleCheckStateChange(final CheckStateChangedEvent event) {
        BusyIndicator.showWhile(getShell().getDisplay(), new Runnable() {
            public void run() {
                IResource resource = (IResource) event.getElement();
                boolean state = event.getChecked();
                tree.setGrayed(resource, false);
                if (resource instanceof IContainer) {
                    setSubtreeChecked((IContainer) resource, state, true);
                }
                updateParentState(resource);
                validateInput();
            }
        });
    }
    /**
     * Displays an error message when a CoreException occured.
     * 
     * @param exception the CoreException