I've had an issue with the editor breaking on ie10 (and some other browsers but works in others). It works in IE's compatibility mode but not normally. Symptoms are:

1) Drop Lists won't respond - sometimes throws an error that it can't setCapture()...

2) WYSIWYG mode in editor doesn't render its output correctly (h tags not working etc.)

3) right click in WYSIWYG window doesn't bring up context-sensitive menus, just IE's normal right-click pop-up.

I post to let others know who are facing this issue what resolved it for me. It was some bad custom coding in the common.config file in the configuration\shared folder. I replaced with a fresh copy of the common.config file from the current download and all is well.