I'd like to move forward with publishing the flexible box model as a working draft. There have been specs floating around for years, but it's never been published on the TR page (despite, I believe, a minuted group resolution to do so at one point).

I think the newest draft is http://xulplanet.com/ndeakin/xul/specs/flexbox.html . (There's also an older draft at http://www.damowmow.com/temp/csswg/old/ui/flexbox.html .)

I propose we use the shortname css-flexbox; I'm willing to import it into dev.w3.org space and prepare it for publication if needed.

There's a good bit more technical work needed in writing up the details of the layout algorithm in mathematical form (and also in adding more examples, or readding dropped ones from the older spec). However, I don't think that prevents us from publishing it as a working draft so that we can get wider feedback on the material we have so far.

I'll briefly summarize the reasons for this specification:

The flexible box model module adds features to the CSS box model that provide some of the basic formatting concepts often used in user interface layout. Much of the specification is implemented in both Gecko and Webkit (with prefixes), and this implementation forms the basis of the formatting model of XUL, the language used to build the user-interface of Firefox and a number of other applications. These formatting concepts have a good bit in common with other user-interface layout systems.

Although many Web pages are essentially user interface, or documents in the middle wrapped in user interface on the edges, they are laid out using formatting primitives designed for formatting documents, causing much frustration for authors. The goal of standardizing this material at the W3C is to provide Web authors with formatting primitives that are more capable of representing the layouts that they want to achieve while effectively using the space provided by browser windows of varying sizes. (I talked about this in a good bit more detail in my talk at XTech two years ago; see http://xtech06.usefulinc.com/schedule/paper/146 .)

-David