Inline diff in single plane view does not show

What steps will reproduce the problem?

1. Switch to single pane view
2. Enable inline diff

What is the expected output? What do you see instead?

Expected: Visualization of things removed and things added inside the given line. Actual: Old version of the given line is displayed with a single color, the new version of the given line is displayed with another single color.

What version of TortoiseGit and Git are you using? On what operating system?

TortoiseGitMerge 2.2.0.0 - 64 Bit, Jul 2 2016 libsvn_diff 1.8.0, -dev apr 1.5.2 apr-util 1.5.4 Windows 7 Ultimate

Please provide any additional information below.

GitHub's commit view shows a possible visualization of inline diffs in single pane view (they call it "Unified" view).