It is seen that on the setting page, sorting of each panel is missing. If sorting is made enable, a little bit easier to administer the plugin setting page.
Also, downward arrow on hover on panel title is missing...
But it can be easily fixed with the following -
<div title="Click to toggle" class="handlediv"><br /></div>
putting the above code in HtmlPrintBoxHeader method in sitemap-ui.php
check this image