[melagonster]

more interesting part is, when you find these are shared in powerpoint and word, too.

there is not warning about I modified another file, if I dare to work on multiple task, everything probably wreck.

[fomine3]

Devil's advocate: For Excel, it makes a bit sense to have app global undo because sometimes Excel books refer other opened books' data. For Word and PowerPoint, it's hard to advocate because I've never seen referring other docs.