Safari Version 6.2 (8537.85.10.17.1) scrolls down one line for every character I typed in https://www.mediawiki.org/wiki/Help:TemplateData
I was not able to reproduce this in Firefox 32.
Version: unspecified
Severity: major
See Also:
https://bugzilla.wikimedia.org/show_bug.cgi?id=71119