Every time I copy a button and change the sprite, it reverts upon pressing apply. This is with an existing project. I have not had a chance today to start a fresh project and get the exact steps required to reproduce the issue, but I cant imagine it would be too different.
Just to clarify, what I am currently doing is:
Copy button (consists of sprite, button, collider, button scale)
Change new buttons sprite
Apply prefab
New button reverts to old buttons sprite.
To be clear, I definitely did upgrade NGUI properly (nuke it from orbit), and am definitely running the latest version.
Ill try get a reproducible from a fresh project when I get the chance. Its a busy week