.animate does not play well with css display: box; (and inline-block as well)
The .animate code doesn't play well with css' new box display type. When animating a width or height jQuery sets the display to block breaking the content in the box, despite the fact that box model content works perfectly fine with animation.
Line 5738 of jQuery-1.4.2.js has a statement:
this.elem.style.display = "block";
.animate can be made to play well with box display with a condition like this to test the display type.
this.elem.style.display = /^(-(moz|webkit)-)?box$/.test(this.elem.style.display) ? this.elem.style.display : "block";
If you're worried about future proofing the vnd prefix test can be replaced with a wildcard to avoid breaking in any future implementation.
This is also making me think that jQuery is probably screwing up on inline-block as well. (confirmed; Yup, jQuery messes up inline-block as well, and inline-block animates perfectly fine if jQuery didn't break it)
Along that line, this could work better;
if ( !/^(-[^-]+-)?box$|^(-moz-)?inline-block$|^-moz-inline-stack$/.test(this.elem.style.display) )
this.elem.style.display = "block";
I don't see anything wrong with adding this. I'm not asking for jQuery support for the unfinished spec, just that jQuery doesn't completely barf when trying to use it in situations where you don't need to bother with compatibility and have a use for it.