Bug 211610 [Forms] Adopt new MPE key binding API
bundles/org.eclipse.ui.forms/src/org/eclipse/ui/forms/editor/FormEditor.java
* -1, or <code>null</code> if it is.
	 * 
	 * @return active page instance if selected, or <code>null</code> if no
	 *         page is currently active.
	 */
	public IFormPage getActivePageInstance() {
		int index = getActivePage();
		if (index != -1) {
			Object page = pages.get(index);
			if (page instanceof IFormPage)
				return (IFormPage) page;
		}
		return null;
	}
	/**
	 * @see MultiPageEditorPart#setActivePage(int)
	 */
	protected void setActivePage(int pageIndex) {
		
		
		if (pages.size() > pageIndex
				&& pages.get(pageIndex) instanceof IFormPage) {
			pageChange(pageIndex);
			IFormPage activePage = (IFormPage) pages.get(pageIndex);
			activePage.setActive(true);
			super.setActivePage(pageIndex);
		} else
			super.setActivePage(pageIndex);
		updateActionBarContributor(pageIndex);
	}