Can we animate the width or height properties of an element without causing expensive reflows, in order to reveal or open a menu? If so, how? An alternate question might be: can animation of width/height be hardware accelerated by the GPU in certain cases?
EDIT: Changed the title from “Animating CSS width/height without performance loss from reflow?” to “Hardware accelerated animation of CSS width/height”.
If hardware acceleration is not possible, that’d be an nice thing to add to browsers. For example, when no element in a parent container ever need to reflow when the parent is re-sized, then it’d be nice for the resize animation to go to the GPU.