Dzerzhinksky's statue stood in front of the Lubianka right up until the implosion of the USSR. He was never purged and the name wasn't changed back until the implosion. The commies there are now trying to return the statue to its place.
http://www.eng.yabloko.ru/Publ/2002/papers/upi-160902.html
Thank you for the information.
I don't believe I said Feliks was purged, I believe I said the square was renamed when he fell from favor (what, 1990, 1991?).
I look forward to being corrected or updated as needed. Your info is quite good.