Vim loses undo history when changing buffers

Question

If I\'m working in a file, change to another buffer, and then change back, I have lost my undo history.

1. vim File1.txt - make a bunch of changes &

Answer 1

You could :set hidden. This means that the buffer of the old file will only be hidden when you switch to the new file. When you switch back, you still have your undo history.