@jernej__s @Canageek @aesthr to be fair, I have genuinely seen a lot of inter-document linking and data loading amongst finance teams where as word documents are usually separate. That might also go some way to explaining why word went SDI about 15 years before Excel…

@aesthr Excel used to have a multiple document interface (MDI) When undo redo was rolled out, it was visually and logically associated with the single application and applied to all of the multiple documents open within the application. So visually, it was more logical back then that you would expect undo to be at the application level as all open docs were visually in the one app. There was some logic to supporting undo/redo at the application level, to be able to cleanly undo changes which imported or linked data across multiple docs. But visually, when they changed to an SDI it was very unobvious that that this is how undo would work and although they changed to the SDI with a menu per doc they left the single undo-redo stack implementation from the MDI. Arguments would’ve been backwards compatibility and being able to cleanly undo changes that spanned documents.