With the old change screen, we can "easily" rebase a patch series by going to the first patch of the series, click the rebase button, then do it for each patch of the series (in series order).
In the new change screen this does not seem to work, first because its hard to navigate a patch series in series order, secondly because the rebase button cannot be used in patches that are not the first of the series.
We need a solution to perform rebase of a patch series from the web UI that works (at least as well as when using the old change screen) and that is easy to use (possibly a solution that would let you select a bunch of patches and do a rebase of the whole series with a single click).