This was caused by the `notes` global class not existing when the
`file_comment_button` code is run. The notes class was used to check
if the diff is currently in parallel view or not. To get around this
I've added a check into the `file_comment_button` JS to check if the
view is currently parallel or not.
Closes#38117
This commit moves the rendering of the button back to the server, and
shows/hides it using opacity rather than display. It also removes the
transform applied to the button on hover (scale). Previously, both of these
factors automatically triggered a reflow, which creates a performance
bottleneck on pages with larger DOM size.
MR: !12103
It now shows the line will be commenting on my highlight the line number cells with a lighter color. The button has also been made smaller, it was previously way over the top & took over a lot more space than it should of done
Closes#27543
yukihir0