Intellij - Pink bar on the side - what does it mean / do?

Question

A pink bar appeared on the side, just like the git changes, but it doesn't seem to do much.

What is it's purpose?
Why is it there?

Clicking on the "show diff" button does show a diff, but it is not the entirety of the bar (just one line). The "AB" button does nothing.

Answer 1

This is called 'Review Mode', and its purpose is to facilitate easier review of PRs. However, I don't know why it randomly activates when I am not actually reviewing any PRs. That said, you can turn this mode off by clicking 'Disable Review Mode', as shown in the screenshot below.

Answer 2

According to a search on the IntelliJ help website for the term "pink", I got one response.

4. Select the file you want to investigate, right-click it and select Jump to Source from the context menu.

   In the file that opens, pink markers in the gutter indicate the changes that are available for review. Clicking these markers reveals a popup displaying the original code.

Source: Work with GitHub pull requests (emphasis is my own)

I can't see enough of the code in question to verify that the pink bar does actually indicate the changes that are available for review.