A few comments however:

- when presenting non mandatory fields to the users, this approach is less explicit than some “traditional” layouts for presenting multiple boxes directly on the screen. Ultimately, if the user does not see the possible options all at once, he will probably not take the time to expand each individual box in order to select different options.

- this presentation is much neater than the traditional layout but it also involves more clicks (in some cases this is not a problem, but in others this is a relevant indicator of form performance).

- Visually, the boxes you created look awesome. I would only adjust the border color of the popup box to a lighter blue in order to match the outer border from the title bar. I would probably try with a 1px so that it seamlessly prolongates the top bar style.

- In your example, the last box title takes 2 lines to display, but the popup shows above the second line of text. Ideally, there should be some way to automatically adjust the offset of the popup box in order to keep the title bar readable to the user while the popup is visible.

Yet, I really like how your example look and the idea of showing a summary of what is selected in the title bar is definitely a clever one. These kinds of nice small details are indicative of good web 2.0 apps nowadays.

Thanks for sharing this!
Michael.