Diff toolbar button for overriden shadows?

[saqimtiaz]

I have a vague memory of a toolbar command or similar for showing a diff between the current version of a tiddler and its underlying shadow.

Does such a thing exist in the core, or am I perhaps recalling something I or someone else prototyped at some point?

[Jermolene]

It's one of the core preview options:

[saqimtiaz]

Excellent, thank you.