jQuery UI SelectMenu - Positioning becomes offset after value change

I have a simple fiddle set up that attempts to illustrate this, but essentially what is happening is, using the jQuery UI SelectMenu plugin I am having an issue with positioning being drawn improperly whenever I have to programatically tell the SelectMenu to update it's value.

Seen here, I have two boxes. They should both be 250 px wide, and the first one is. The jQuery SelectMenu plugin does not automatically update to respond to the change in the first, and so I manage this binding via the javascript library KnockoutJS. When I programatically inform the select menu that it has changed, I think it is getting completely redrawn and as such is getting very awkward sizes.

http://jsfiddle.net/ciel/qgJt7/

ca开发者_StackOverflow社区n anyone offer some help?

---

Somehow I think you are making the problem more complicated than it really is...

Is this what you want to achieve?

http://jsfiddle.net/william/GJuAL/