If I want to compare, for example, V2 to V1, when I enter comparison mode, the comment stream for V1 is not visible to me. Document reviewers may be checking to make sure many comments from V1 were resolved correctly. Comparison mode is usually a useful way to do this, but without the comment stream in the previous version, comparison mode becomes much less efficient for the reviewer. It would make comparison mode much more robust if the reviewer could toggle comments from previous versions on or off.