User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:2.0b8pre) Gecko/20101202 Firefox/4.0b8pre Build Identifier: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:2.0b8pre) Gecko/20101202 Firefox/4.0b8pre Seeing various other bugs related to messed-up rendering of the tab view i wondered how this could even happen. After taking a look at the view with the dom inspector the problem became obvious: Tab groups and tab items are all direct children of the body element instead of tab items being nested within their owner group items and all layouting seems to be done manually. This is suboptimal for several reasons: 1. it complicates code, since all tab items have to be manually positioned to appear above their groups. 2. it doesn't make full use of retained layers. Consider a group being moved, all previews inside the group would retain their position relative to the group and thus the entire content could be retained and just moved around by compositing instead of moving around each individual item. 3. it makes it harder to style things via css (think of addons extending tabcandy) Since TC is using a stripped-down version of jQuery, here's something that would not only obsolete any manual position in a group with a grid-layout but would also take care of sorting: http://jqueryui.com/demos/sortable/#display-grid jQuery UI draggable/droppable could also take care of moving things from one group to another. Stacked groups would be somewhat more complicated but could make use of CSS3 rotations and nth-child rules. So most of the tab layouts could be expressed with 2 CSS global rules + 1 additional per-group rule. Reproducible: Always

This sounds great. Time-frame-wise, we're coming down to the wire and are going to concentrate on the existing perf work and fixing things that are broken.

We're not going to address this with Panorama being slated for removal.