Since DOM insertion and deletion is much more performance-expensive than, I would recommend that your `spaceBlockingElements` selector check to make sure it's not adding a duplicate spacer in the first place.

And actually, I think it's ok to leave the two seperators that might exist because a table was deleted. They'll get stripped out from the XHTML due to their class and I don't think they will confuse a user at all. Not worth paying the performance penalty if there's really no benefit to doing the extra DOM selection work, especially in a code-path like this that's hit so often.