Internal diff tool in FB3 sucks big time. It worked in FB2, but someone decided that this thing is too good for this world and changed it. This ugly proportional font and this terrible performance are just unbearable!
Single diff on 1000 lines files takes around 50 seconds. Multiply it by 10-20 per day and this is a stolen time from you.
It is time to change this. Here is the place to vote for this bug:
http://bugs.adobe.com/jira/browse/FB-12492
Sweet Adobe, please have a mercy on us all and give us back the
simple, no-gimmick diff, which just works.
Cheers!