Option for swapping-out used LSAT questions

I love using this site to practice for the LSAT. However, each time I see a question or test that I have done before I get frustrated. There is no way to tell the system I have already seen the contents and thus need to swap it for a fresh one. Some times I have seen the content from study unrelated to Khan Academy, and sometimes I viewed the content on Khan Academy just a week or so ago. 

Practicing for the LSAT is not meaningful if a good percentage of the practice is on problems I have already done before. There needs to be a "Seen this before? Click here for a new question/test/section!" button. 

It should be a simple task to keep track of what question sets have already been seen by a user, and it shouldn't be that much more difficult to implement a swap button. Thank you!