This is an artifact of a window that should be invisible, but unfortunately is being prevented from being invisible by anti-virus software, anti-spyware software, anti-ad software, Internet Explorer, or some other program. At this point, a small number of people see this issue, and I cannot reproduce it, and haven't been able to pin it down to any program in particular.
If anyone out there is seeing this and wouldn't mind doing a little bit of testing, email me at support@thetournamentdirector.net. I'd like to have you try a beta version with a test-fix in it.