Great plugin first of all.
But just thought I'd let you know that I updated the plugin today from 1.1.1 to 1.2 and shortly after went to wp-admin/widgets.php and...
the black admin strip across the top was gone,
the widget area down the right hand side was gone,
plus all the popouts in the left side menu didn't show.
That's as much as I noticed before trying to figure out a solution. I had only updated two plugins this morning so I rolled WP-user-control back to 1.1.1 and hey presto my widget admin page is working as it should.