While finalizing the layout of secThe current relaxation implementations, relaxation of a fragment may is not correctly adjusting the
change the size of other fragments depending on itsize and offsets of fragements in one section based on changes in size
of another if the layout order of the two happened to be such that the
former was visited before the later. Therefore, we need to invalidate
the fragments in all sections after each iteration of relaxation, and
possibly further relax some of them in the next ieration. force toThis fixes
calculate the offsets of fragments each time relaxation happens.