[ePierre]

> it seems control-z does nothing

Normally v2.4.0 improves this. As stated in their release notes: “Add undo support for masks and more intelligent grouping of undo steps”.

Basically, in v2.2, even low-level operations that didn't have a visible impact were in the undo list, so when you pressed Ctrl+Z it would undo something, but you wouldn't see any change. You would actually have to press Ctrl+Z several times to finally see something on the screen.

This was changed and should be more human-friendly :)

> how do you understand the history function?

This is indeed a little bit more complicated that just a list of things to undo. You can read a bit more about it in the user manual: https://www.darktable.org/usermanual/en/darkroom_concepts.ht...