Today I made a simple one-line change to the last line of the earliest post (i.e. the one at the bottom). When I next viewed the site, the SIDEBAR had been corrupted. Instead of displaying in a column parallel to the posts, it is (still) along the right side, but displays *below* all of the posts instead of beside. It's as if a table structure is goofed up. So at first, it looks like the sidebar has disappeared. When I change the theme from WordPress Default 1.5 to WordPress Classic 1.5, the sidebar displays correctly. Did the Default theme get corrupted? How? How do I fix it?