Issue Summary

The count of lines hidden doesn't appear when hovering over the hidden line horizontal bar. It only appears when you hold shift.

This is reproducible on Data Center: You betcha

Steps to Reproduce

1. Open a PR diff
2. Hover over a section of code that has been hidden because it has no differences

Expected Results

The message when hovering should say something like: "4193 lines hidden. Shift + click to show all lines"

Actual Results

The message when hovering omits the count of lines. Showing only "lines hidden. Shift + click to show all lines":

Weirdly, when you hold down Shift whilst hovering, the count appears: "4193 lines hidden." (The "Shift + click to show all lines" is removed, as expected, because the user is already holding down Shift).

Workaround

Hold down Shift to see how many lines have been hidden.