I have been preparing some questions on CF groups, If I change a problem statement and add it in my Contest in Groups , the users who have solved that problem previously are shown green box on submit button beside the question in Dashboard (meaning the Question has been solved previously) in the group contest, So even if I change the whole problem statement it takes the users very less time to find the problem they have previously solved. I suggest the Codeforces team to please disable this feature if possible so we can use Codeforces Problemset more easily in Groups.