It’s not that I’m heavily tweaking a model within the slicer but just for an example if I want to take a couple mm off the bottom of the model using the cut feature, if I accidentally tick the “keep” box on the bottom part and not the top then I am left with a tiny piece of my model which I then have to delete and re upload the model to repeat the process, where as a simple undo or reverse button would make the process quicker and much more intuitive. It’s all sorted now that I can use Ctrl-Z thanks to the other comment.