On the main page, index.php, the calendar looks and behaves like it should. However, if I click on the previous month, the whole first week in the calendar moves to the right. Just the first week. The other weeks are fine.
Also, if I click on a post title, and the single page comes up, the first week of the calendar shifts a few characters to the left. ???
I've noticed the problem with previous versions of wp, with any theme, including the default one, and with ie and firefox.
What's causing that and how do I fix it?