Steinsaltz Controversy?

A little while back I used a Gemara with annotations by Rabbi Adin Steinsaltz. This was the Hebrew edition and not the English version published by Random House. A Rebbi pointed out to me that the Gedolim, especially Rav Shach ZT”L, were against the use of such Gemaras and banned them. Can someone please explain the whole situation, particularly the reason why they were banned?