I found the following quote in a review of the new "Bewitched" movie:
"In the first show [the old sitcom], Darrin’s ex-girlfriend invites them to dinner and is a total b*tch. Samantha causes her dress to collapse and her wig to fly off. The movie goes to the trouble of recreating that episode but without any of the comic brio."
http://www.steynonline.com/index2.cfm?edit_id=26
It seems that the same scene appeared in both the movie and the old sitcom. Here is a site that contains the sitcom version. I could not open the video. The site appears to be a Russian site that confuses the actress' names.
http://womeninwigs.narod.ru/embarr_video1.htm