To reproduce:

• Start by viewing the "changes since last review" for some revision that has gone through a couple diffs. That is, be looking at the difference between some middle diff, and the last diff.
• Add some inline comments. Don't submit them.
• Switch to viewing all changes. That is, from the base, to the last diff.

Observed:

In the preview area, the inline comment preview says the inlines are "Not Visible":

{F151675}

Even though they totally are visible:

{F151677}

Clicking on "Not Visible" does nothing.

Interestingly, if you add another inline comment at this point, the problem goes away.

Expected:

"Not Visible" should say "View". Clicking it should scroll the view to the inline comment.