Both reasons the channel-rows idea existed are gone. It was written when the
sidebar was flat and unstyled; v1.10.0 gave it row surfaces and it already groups
pinned and auto-tell tabs under headings. What was left was a change to how the
plugin is operated rather than how it looks -- and tabs are what users have
learned to use.
Next two are the input bar and the first-run wizard, the last surfaces still
drawn in ImGui defaults.