No "Processing" message when changing client selector

The "Processing" message works great when clicking on column headers or when paging, but it should also appear when the client selector is changed - and filters are applied.
Looking at the code it looks like it should work. Not sure if I'm missing anything?

Start by tracing the client selector change and filter-application flow, then compare it with the column-header and paging handlers that already show the "Processing" message. Done means changing the client selector displays the message while filters are applied, consistently with those existing interactions.

Written by the indexing model from the issue text.