The Difference transform requires 2 upstream items. Each upstream item can be an Input or a Transform.
The Compare Data window requires 2 items to be selected. Each selected item can be an Input, Transform or Output.
Well, interesting. I must have not had two things actively selected. I see the compare works fine with transforms.
1 Like
For quick comparison I use EDT directly
For heavy comparison I use EDT to clean files and XLCompare… to compare 
Difference transform now available in v2.9.0.
1 Like