when typing in textarea by using IE8 the text is scrolled automatically.

It looks like a IE-Bug http://connect.microsoft.com/IE/feedback/ViewFeedback.aspx?FeedbackID=432377.
With Google I found a user in a forum (http://www.winvistatips.com/jerky-scrolling-ie8-t336964.html#post_message_1433811) who says:

"In all the cases I've seen this has been to do with storing the "caret" position of the cursor in the textarea so that additional functions, such as inserting text, can be done at the last cursor position rather than the start of the textarea."

That sounds like a problem with [[MediaWiki:Edittools]]. Thanks for have a look in it. (works fine in compatibility mode)

Version: unspecified
Severity: enhancement