Bug 174272 FileStoreEditorInput needs to be restorable
3.3 M5 The FileStoreEditorInput needs to restorable on startup. Therefore it needs to return an IPersistableElement and there needs to be an element factory.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/ide/IDE.java
* editor is brought to front; otherwise, a new editor is opened.
	 * <p>
	 * 
	 * @param page
	 *            the page in which the editor will be opened
	 * @param input
	 *            the editor input
	 * @param editorId
	 *            the id of the editor extension to use
	 * @return an open editor or <code>null</code> if an external editor was
	 *         opened
	 * @exception PartInitException
	 *                if the editor could not be initialized
	 * @see org.eclipse.ui.IWorkbenchPage#openEditor(IEditorInput, String)
	 */
	public static IEditorPart openEditor(IWorkbenchPage page,
			IEditorInput input, String editorId) throws PartInitException {
		
		if (page == null) {
			throw new IllegalArgumentException();
		}
		
		return page.openEditor(input, editorId);
	}
	/**
	 * Opens an editor on the given IFileStore object.
	 * <p>
	 * Unlike the other <code>openEditor</code> methods, this one can be used
	 * to open files that reside outside the workspace resource set.
	 * </p>