I found my custom maps screen looked like this after I deleted a few maps
exiting and re-entering the custom map screen fixed it.
It's not really important, just something if there is a next update
Maybe you can also post a screeny of how this screen is supposed to look. Did you play maps before and should there be more of them in the list?
Also please describe what you exactly did. Did you click the 'X' in this screen to delete some maps or did you delete them in the Windows Explorer?
This happens if you're deleting maps while there's a scroll bar, if you then start deleting lower maps the scrollbar will shorten and dissapears while you haven't reached the first map yet.