Per bug 417590 comment #29, I only landed basic CSS for the new helper app panel, we still should find a solution that makes icons and labels not jump around in the action select column when a row is selected, and ideally also make the icons and labels in the menu line up horizontally with the rest, so that everything looks _really_ good. I have CSS here that works for me on Linux, but Neil didn't really like that much when doing the reviews in the main bug...