Horizontal scrollbar just shows up at the end of the file in Crucible review

Summary

Horizontal scrollbar just shows up at the end of the file

Steps to Reproduce

1. Add a large file to the review. The file must contain many lines of code and each line must be long.
2. Try to scroll down, and note that the horizontal scrollbar won't show up until the last line of code of the file is reached.

Expected Results

The horizontal scrollbar should be always present if any line of code in the file is long.

Actual Results

The user needs to scroll all the way to the bottom of the file for the horizontal scrollbar to show up.
This is consistent among different web browsers.