IE9: Entering WIKI-WYSIWYG-Editor produces JavaScript-Error

You have to activate "Display Script Errors" in IE9:
Tools -> Internet Options -> Advanced (tab) -> Display a notification about every script errors (under Browsing category).
If you want to edit a WIKI-page you get the error:
"Effect" is not defined in dragdrop.js and then another error in controls.js.
After you close those two message boxes everything works as intended, but the message boxes are really annoying.
Thanks for the fix!