This may or may not be related to http://drupal.org/node/330964. On a fresh install, when I turn on the resize plugin and resize the textarea, the textarea disables and ghosts itself while I'm dragging, but when I release the mousebutton, it doesn't re-enable. It's stuck in its uneditable, ghosted form.
This happens in FF3 and IE7 for me. I'm using YUI module RC1 with 2.6.0 loaded remotely.