Dynamic sidebar widgets moving around

I am generating dynamic sidebars for all the root pages on a site like this:

foreach (get_pages(array('parent' => 0)) as $post) {
		setup_postdata($post);
		if (!dynamic_sidebar(get_the_title())) {
			register_sidebar(array(
				'name'			=> get_the_title(),
				'before_widget' => '',
				'after_widget'	=> '',
			));
		}
		wp_reset_query();
	}

which works fine… however when I add a new page, the widgets I’ve placed in the sidebars jump around – I guess maybe because it’s recreating these sidebars and the widget relations get lost during this process?

Can anyone tell me how I could do this better?