This is a random error that occurs occasionally with IE. As much as I'd like to fix it, this error is deep in the internals of IE that makes the advanced editor possible. Hopefully, Microsoft will address this problem before their next IE release. Until then, all I can suggest is to reload the page if this happens.
Jason Rhinelander
Gossamer Threads
jason@gossamer-threads.com
Jason Rhinelander
Gossamer Threads
jason@gossamer-threads.com