Unable to use right hand side buttons on pages with inline comments

Summary

On pages where inline comments are present, it is not possible to use the buttons on the right hand side of the page (preventing comments to be added, as well as watching a space, or using the more button).

Steps to Reproduce

1. Add inline comments to a page.
2. Enter some text in the comment text box.
3. Try to click on the Save button.

Expected Results

The comment is added to the page correctly.

Actual Results

Nothing happens when trying to click on the buttons Save, Preview, or Cancel

Notes

Reproducible on all browsers. When looking at the development tools in Chrome, you can see an empty div where the buttons are unclickable: <div class="ic-sidebar"></div>

Workaround

Use Ctrl+s (Cmd+s on Mac) to add the comment.
When loading the page, the buttons are clickable for a short period (less than 2 seconds) allowing you to access the additional options.