Hi list,
cc Pratyush,

While rebasing an old series, I had a 3-way merge fall back that didn't 
show the `||||||| merged common ancestors` very well in git-gui.

That is, the conflict markers, and common ancestor lines, are treated as 
being part of the current HEAD hunk, rather than being separated.

I opened a Git for Windows issue 
https://github.com/git-for-windows/git/issues/2340 and attach the 
screenshot of the git-gui markers.

I've not had any chance to look at the underlying code, but thought it 
worth reporting. I guess the issue has been there a while.

Philip