Firefox Start should adjust automatically and as necessary to changes in viewport width and orientation, and present information in a way that makes the best use of the space available. "snapped", "fill", "split", "landscape", "portrait" can be interpreted as named aspect-ratios and thresholds for a responsive design. They are application states, but it turns out that rather than implementing separate UI for each (with all the performance & maintenance implications that has), we now have the ability to adapt a single UI and the presentation of its content for optimal viewing and interaction in each. Furthermore, with the potential for a myriad of screen sizes, dimensions and configurations, it makes sense to respond fluidly to variations within the preset, named thresholds. NB: This does *not* preclude large-grain changes like the removal of the tab and context bar in snapped view; all those distinctions will remain, only the implementation will change, and our ability to adapt to change.

Changing the title to better reflect dependent work. I'm not sure what this was originally about, but it's currently blocked by misc. layout issues in StartUI.

With no more open dependencies, are we done here?

We're done, resolving!

Mozilla/5.0 (Windows NT 6.2; WOW64; rv:26.0) Gecko/20100101 Firefox/26.0 Build ID: 20130815030203 Built from http://hg.mozilla.org/mozilla-central/rev/a8daa428ccbc WFM Tested on windows 8 using latest nightly for iteration-12. Firefox Start adjusted automatically for "snapped", "fill", "landscape", "portrait" view.