Drupal 6

There's a long-running bug in the Drupal issue queue about a bug that I had to work around this week: when using the Batch API, your site theme will only be used for the first page. As the page reloads to show the progress of the job, the ugly, default Garland theme is used (well, that's not entirely true: it's actually Minnelli, but looks like Garland).

In most cases, this isn't a big deal: during a site install or when running update.php, it doesn't really matter what theme the admins see. In one client's case, though, we're using the Batch API to show progress of a multi-part donation that may take some time to process. In that case, you don't want regular site visitors seeing Minnelli: it's a jarring transition away from the site theme, and to anyone who isn't a seasoned Drupal user, it probably looks like something broke.