Compare View mode: Redo button doesn't display

Description

Steps to reproduce

1. Create blockA in English with text in the main body.
2. Create blockA by auto-translating from English to Svenska.
3. Go to Compare View mode.
4. Click on the main body of the Svenska version.
5. Replace the content by duplicating from English.
6. Select the Autosaved link and click the Undo drop-down button.
7. Select the Autosaved link.

Expected: The Redo drop-down button displays.

Actual: The Redo drop-down button doesn't display. The Undo drop-down button displays instead.