When I am doing it, the working tree is empty.
Second, in the same file I don't want all the changes. Not sure how to do it with cherry pick like you say.
Also more easy and intuitive to allow to diff commit with working tree that i can edit like other git clients that do that.
I already use this feature many time in git extension. But I would really love to see it in smartgit. 

Hello @Marc

Now I become a paying user. I working at Camtek ltd, and we purchase 5 licenses because of me. We willing to buy more if you can improve your amazing app.

As my last topic that decline: #1179

I want to add as you requested more info about: 'Editing the working tree when diffing against an arbitrary commit'

One use case is you want to add a specific things from the arbitrary commit. and not bring all changes from that commit like git cherry pick.
Go over file by file and add the specific things.

I also ask from my colleges that will comment here, and explain in their words why it important feature for us. 

Thank you.