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
public static IEditorPart openEditor(IWorkbenchPage page, IFile input,
			String editorId) throws PartInitException {
		
		if (page == null) {
			throw new IllegalArgumentException();
		}
		
		return page.openEditor(new FileEditorInput(input), editorId);
	}
	/**
	 * Opens an editor on the given file resource.
	 * <p>
	 * If the page already has an editor open on the target object then that
	 * editor is brought to front; otherwise, a new editor is opened. If
	 * <code>activate == true</code> the editor will be activated.
	 * <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
	 * @param activate
	 *            if <code>true</code> the editor will be activated
	 * @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,