disable email when lead assignment is changed

Vote for this Idea: https://success.salesforce.com/ideaView?id=08730000000Z44aAAC

There is no easy solution to this. 

The only one I could spot on this was "The solution of using DML option only works if we use future method after a lead update.  This confuses the user since after the save it appears the lead did not get reassigned, only after a refresh do they see the new user.  A very complicated work around to disable what should be a standard feature for working with lead reassignment through APEX."