While the left and right padding of customization mode animate nicely, the bottom padding just jumps into position. This is particularly visible when exiting customization mode because the entire footer jumps down. The ideal solution would be to animate the bottom padding as well. If that is too much of a performance hit, maybe just leaving the bottom padding as is during the transition and removing it when switching back to the previous tab.

Not animating the bottom margin was an intentional choice so as to (theoretically) reduce the amount of reflowing necessary in the menu panel. It's possible that other work in bug 962657 will mean we can animate the bottom margin again, but until then, or unless this turns out to be a major glitch from UX's perspective, I think we should keep this the way it is.

I've put a dependency here so that we try animating the margin again if / once we solve the panel reflow problem.

(In reply to Mike Conley (:mconley) from comment #1) > Not animating the bottom margin was an intentional choice so as to > (theoretically) reduce the amount of reflowing necessary in the menu panel. That's what I feared :( > It's possible that other work in bug 962657 will mean we can animate the > bottom margin again, but until then, or unless this turns out to be a major > glitch from UX's perspective, I think we should keep this the way it is. Well, if it turns out to be too costly, see comment #0 for a proposal on still somewhat improving the situation.