Confluence allows whitespace-only comments without content

Whether it's in-line comments or a regular page comment, it looks like Confluence will prevent completely empty comments and 1-whitespace comments from being posted. However, it does not validate against or more whitespaces, and will allow these to be saved.

Steps to reproduce

1. On an existing page, add a comment (inline or regular) with 2 whitespaces

Expected behavior

Confluence will display one of these warnings and prevent the comment from being saved:

For regular page comments

Comment text is empty. Cannot create empty comments.

For inline comments

You cannot save an empty comment.

Actual behavior

Whitespace comments are saved