Bug 273012 [Forms] NPE in FormPage.setActive(...)
bundles/org.eclipse.ui.forms/src/org/eclipse/ui/forms/editor/FormPage.java
* @return <code>true</code> if the page is currently active,
	 *         <code>false</code> otherwise.
	 */
	public boolean isActive() {
		return this.equals(editor.getActivePageInstance());
	}
	/**
	 * Creates the part control by creating the managed form using the parent
	 * editor's toolkit. Subclasses should override
	 * <code>createFormContent(IManagedForm)</code> to populate the form with
	 * content.
	 * 
	 * @param parent
	 *            the page parent composite
	 */
	public void createPartControl(Composite parent) {
		ScrolledForm form = editor.getToolkit().createScrolledForm(parent);
		mform = new PageForm(this, form);
		BusyIndicator.showWhile(parent.getDisplay(), new Runnable() {
			public void run() {
				createFormContent(mform);
			}
		});
	}
	/**
	 * Subclasses should override this method to create content in the form
	 * hosted in this page.
	 * 
	 * @param managedForm
	 *            the form hosted in this page.