Black spot page when running locally

As of yesterday multiple people in my company using version 7.23.5 and 7.23.6 of Mendix Studio Pro when they run locally on different apps get a screen with just a large, black dot in the upper left corner and no login screen. Anyone know what the problem is? Here is what it looks like.   The accepted answer below fixed the problem. Note, there were differences in a few files, index.html and login.html
1 answers

Can not reproduce it on my 7.23.5-project running locally. What happens if you start a new 7.23.5 or 7.23.6 project? Do you get the same dot? If not, try overwriting the theme-directory the Atlas_UI_Resources with the new ones.

There is some wierd theme-errors going on in version beta-3. Might be related if Mendix is also modifing related code in 7.23.5/6 although I am not aware of any of these.