If I'm editing two files with vim, changing to the other file ( :bnext, :bprev ) seems to drop the undo history from the open file - hitting the 'u' key reports "Already at oldest change".
For example:
vim testfile1 testfile2
- add some stuff to testfile1
:w
:bn
:bp
u
- eep! can't undo!
Is there any way to keep this history for non-visible buffers?