Do people notice there are questions with blue background and white ones in topic tests?

I read through ppl’s comments on which materials are most useful in terms of difficulty levels.
So far i see EOC( questions at the end of topics on textbook) is a must-read, and then TT(topic tests on ecosystem on CFA website) is also important including EOCs and some other unnecessary questions(more difficult).
And I found that in TT the questions come with either blue or white background.
So are the blue ones EOCs? I really want to know because I’m going through TTs and dont want to go to textbook for EOCs again if I’ve already read through them…