When accessing the messages page on Moodle.org (https://moodle.org/message/index.php) and Moodle Open Source, we encounter an issue related to page scrolling. When the mouse cursor is over the message viewing area, page scrolling does not function correctly. The page only scrolls when the mouse cursor is outside the message area and the message writing field does not appear.

Steps to Reproduce:

1. Access the specific messages page on Moodle.org (https://moodle.org/message/index.php).
2. Attempt to scroll the page using the mouse scroll wheel or scroll bar.
3. Notice that page scrolling does not occur if the mouse cursor is over the message area.
4. Page scrolling only works if the cursor is outside the message area.

Demo Video: A demonstration video of the issue can be viewed here: https://youtu.be/lXBCcYE6i1s

Impact: This issue negatively impacts user experience when navigating messages on Moodle.org and Moodle Open Source, especially when trying to interact with and respond to messages.