I hope I can describe it with good words.
I have a bass line c1, d1, e1. I transpose it up with the transpose function. With the new function in 10.2.1 this transposition is shown in the midi editor. When I now use this "fold button" so only the active notes are shown in the midi editor nothing is shown because logic still thinks the notes are at c1, d1, e1 and not c3, d3, e1
Michael