I haven't upgraded to 2.6.1 so maybe it's solved there, but I've noticed an annoying problem recently.
When I save modifications to pages, sometimes the template and parent options disappear. When I click "go back" I get a 404 since it's no longer in the hierarchy where it belongs.
On a related note, didn't a recent version of Wordpress automatically redirect to a page when you entered the wrong path? I liked that feature. Any reason it's gone?
For that matter, didn't there used to be a concise description on the wordpress site of the changes and additions in any update or new release? Where are those now?
