Redesigning site kills Bing rankings?

[kneukm03]

I'm wondering if anyone else has had the experience that a minor site redesign completely destroys your rankings in Bing. I've had this happen three times so far to sites that were ranking #1 for tons of keywords, and are now nowhere to be found.

The sites are all very old (3-4 years), and all I did in the redesigns was essentially to add a sidebar on the left with some graphics buttons and a new graphical header. The text is all the same. None of them are penalized (I checked in the Bing webmaster tools control panel).

Most interestingly, for one of the sites I only redid the home page - I didn't redesign any of the sub-pages. Only the homepage got hit (and was even removed from the index for awhile).

I'm wondering if anyone else has seen this, if anyone knows if there's some kind of very sensitive "new content" filter in Bing, and whether anyone has had their sites recover.

[bwnbwn]

Were all the sites done at the same time or over several weeks? Also did they all go down at the same time?