Working with GitTools in VS 2017 seems to work fine, but for VS 2019 the "Git Changes" window only seems to work until the first commit. Clicking the "Refresh" button after that point shows the files that were recently checked in, not the active changes in the working directory since the commit.

There doesn't seem to be any remedy for this except to close the solution and reopen it, then it will show the correct changes to the working directory until the next commit, then back to the problem again not showing the changes to the working directory until the solution is closed and reopened.