Cursor jumps to subject line when body is scrolled and headers hide / reappear

[kevshub]

Prerequisites

• I have searched for duplicate or closed issues
• I can recreate the issue with all plugins disabled

Describe the issue

When a user replies to a html message in the html editor, if you place the cursor and start writing, then scroll down to read the historical thread - when you scroll back up the cursor jumps out of the body and into the subject input box. It appears to happen at the exact moment the "compose-headers" re-appear after being hidden on scroll.

What browser(s) are you seeing the problem on?

Chrome, Edge

What version of PHP are you using?

v8

What version of Roundcube are you using?

v1.6.7

JavaScript errors

No response

PHP errors

No response

[andevz]

Having the same issue.
RC 1.6.9

[alecpl]

Same in master and Firefox. And it's not only on a reply. It's with any HTML content (that scrolls the page).