[lrivers]

If you are looking for counter examples, take a look at Excel on windows. It undoes in multiple windows.

Say you have two documents open. You make a change in the first then change the second document then go back to the first and make a change. One document has two changes and the other has one.

First undo impacts document one. Second alters document two. Infuriating

[EvanAnderson]

Yes. This is arguably the most infuriating implementation of undo/redo that I've used in any application.

It's worse than an undo that just wipes-out the document. In that scenario I'd just not use the feature.

The behavior in Excel tricks you into using the feature by working as you'd expect in a single document scenario. Then you open a second document and end up trashing one or the other when you undo the wrong thing.

I don't know how anybody ever thought this implementation was the right answer. Ever.

[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.