I'm working with several files opened at same time. Parts, Assembly and Drawing Layouts.
What I did;
1- On drawing page I added some general dimensions (or whatever)
2- Change active file, the part for the drawing I am currently working on.
3- Modify length of the part.
4- Come back to drawing page, making it active.
5- While drawing is active, if I hit undo now, it will revert modification done in previous file that is still open but not active.
I think it would be better if undo was limited to current active file, or undo memory split between active files. As it is right now, I may undo stuff from parts and assemblies while only seeing under my eyes a drawing layout on my screen.
I think this is problematic especially since by default Inventor has the undo command in every possible marking menu context. Undo is really easy to miss click when using allot of marking menu and since it can undo stuff in another inactive file, chances are I won't even realise that I "undid" anything at all.